Dan and Blair started out as enemies in Season One, but because of Serena (Blair's best friend and Dan's then-girlfriend), they were seen interacting with each other from time to time, but only when Serena was involved. Later as the season progressed, Dan was the one who comforted Blair after being humiliated by her own mother and Serena. Thus begun the start of their friend/enemy relationship.Season Three, Blair and Dan still have the whole "frenemy" relationship going on, but started to warm up to one another. Finally, in the Fourth Season, they slowly become closer after teaming up against Juliet Sharp, this time in order to 'save' Serena, and realizing that they both share a variety of interests, such as watching old Hollywood films, art exhibits, etc. They are depicted as the two intellectual-equals in the show. Blair also admits that she fears him as a rival in Damien Darko, when they both are interns at W. They share other similarities in their personalities: they both work hard for what they want and they are fiercely loyal and protective of the people they love. Their respective previous important relationships (Blair with Chuck and Dan with Serena) left both of them heartbroken due to their former lovers' volatility and bad behavior.
In the Fifth Season, Dan still possessed feelings for Blair. Blair, however, had seemed to have forgotten any romantic feelings towards Dan due to her upcoming marriage to Prince Louis Grimaldi of Monaco. However, Blair ends up not being happy because she still has romantic feelings for Chuck. After a terrible accident, Blair starts going to church with Dan accompanying her. Blair has second thoughts about the wedding, but carries on with it anyway. Chuck realizes that Dan is still in love with Blair, and sees him as a rival. Dan and Blair's relationship starts to develop romantically on Valentine's Day when Blair and Dan kiss for the first time. Dan and Blair kiss again in the next episode. Dan and Blair began dating in The Princess Dowry, but their relationship is up in the air as of the season five finale, The Return of the Ring.
Early seasonsDuring the first three seasons, the interactions between Dan and Blair were minimal as most of the time Blair and Dan would only ever interact if it involved Serena. However, in Season 4, they start to get closer after Blair makes Dan realize that he is spending too much time sacrificing his life and interests for Serena and Blair realizing that she and Chuck can not be together until they sort through their lives. After both Dan and Blair realize that they share very similar interests and are the most 'brainy,' they come together and deepen their friendship. Eventually, they embark on a romantic relationship.
Blair and Dan become closer after joining forces to take down Juliet for Serena. While it was their initial bond, it becomes clear that over Christmas had been going out together voluntarily, watching movies at the same time and in the same place, but separately.Dan and Blair's relationship develops further and it becomes clear that the two of them have become friends, are reluctant to admit it. This relationship clearly is good for each of them: Blair while hanging out with Dan seems to forget about her problems with Chuck, with Dorota's words she's "Too Happy, Content" and with her own words, she has "Found Her Center". On the other hand, Dan, starts writing again and indeed succeeds to submit an article to Vanity Fair (thanks to Blair's help). As the two of them keep seeing each other (secretly) they start to question their friendship,and Dan thinks there may be more to the friendship, so in Episode 17 (Empire Of The Son) he comes to Blair's apartment and suggest that they kiss, so that they can know without a doubt if there is something more between them.
After the mid-season term we see Dan checking his phone and having a conversation with Eric about the kiss he shared with Blair. Even though he denies that he likes Blair, he gives himself away with his own words and Eric therefore is the first to find out that Dan is "Ass-backwards crushing on Blair Waldorf". We learn from this exchange that Dan has been waiting a whole week for Blair's text or phone call but she has mysteriously been ignoring him all week. Chuck on the other hand wants Blair back. Knowing that the obstacle to their relationship is the fact that Blair wants to become a powerful woman before becoming Chuck's girlfriend, he thinks he need to solve this issue. Therefore he asks Epperley to hire Blair as her assistant in the Modern Royalty photo-shoot. Epperley calls Blair who in the meantime has told Dorota that she's had an epiphany about her romantic future but doesn't want to deal with it. She accepts the job and while working she tells Epperley that she had a life changing kiss. Epperley informs Chuck about the news and he goes to Dan's in order to find out who she kissed (he thinks it might be someone from W, where Dan worked). Dan learns, via Chuck, that Blair said the kiss she had was life-changing, and clearly impressed by this piece of information, starts rambling about how much Blair is better when she's not around Chuck.("She's intelligent, She's intuitive, She weeps when she watches Nights of Cabiria") and finally tells Chuck that if Blair's happy, he should let her be. Chuck has now understood that is Dan the one who Blair has kissed, and we see him exiting the loft and calling Epperley to ask her "One More Favour".
While Dan is getting ready he phones Eric for some advise but all Eric can say is "You Really Like Her." He also naively believes that Blair concocted this event to elevate Dan's social statue. When he comes to the fashion book thinking Blair called him here both of them find out it was Chuck's idea and all Blair says to Chuck is "Dan May Not Be Royalty But at Least He's Not a Child". And she leaves him all alone and apologises to Dan for what Chuck has done. Dan accepts her apology but still has feeling for her and hides it.Then Louis, the Prince of Monaco arrives in the Upper East Side wanting to see Blair again. They agree to meet for lunch in Veselka in Brooklyn, and that no one must know about their relationship. Meanwhile, Dan has been hired to write about Louis, but once he realizes that Louis is seeing Blair, he drops the assignment. Initially he feigns nonchalant about her being on a date, but he isn't happy about the idea of her being with Louis.
Louis' parents realize why he's in New York, and his handler arrives to check up on him. Lucien, his handler, doesn't know about his relationship with Blair. Both Louis and Blair want him to believe that they are only friends. Blair tells Dan that she has a brilliant plan to keep proving to Lucien that she and Louis aren't in a relationship. She and Dan will kiss at the Pink Party, and Louis' handler will believe that she is dating Dan instead. She tells him that she found out why he was at the restaurant, following Louis, and that this kiss is essential. Initially Dan doesn't agree, but once she mentions that Chuck already knows about their previous kiss, he says he will help her stage a kiss at the party later that day.They arrive at the Pink Party, and have to stay away from one another so that no one (especially Serena) will know they are friends. Meanwhile, Serena, suspicious, has asked Charlie to flirt with Dan and see what happens. Blair jumps in, acting the part of a jealous girlfriend, and she and Dan leave upstairs. Charlie follows them. They stage the kiss for Lucien. When they are walking down the stairs, there is a Gossip Girl blast, and their kiss is broadcast on to everyone at the party. Charlie emerges from upstairs, and there is a second where Dan realizes what has happened, before Blair pulls him away to find Serena so that they can explain. Everyone at the party assumes they are together, and because Lucien is there, they affirm these suspicions.
Serena confronts them about the kiss, and Dan and Blair quickly try to explain to her that it was staged and means nothing to either of them. She asks about their previous kiss, and Blair tells her it only confirmed to her that she wanted to be with Chuck, not Dan. Dan leaves Blair and Serena to talk, and Serena confronts Blair about her secret friendship with Dan. She accuses Blair that she only wants to be Dan's friend because Dan was once hers. Blair defends her relationship with Dan, claiming that they have a real connection. She tells Serena that she will no longer be in her shadow and that she and Louis will be together and happy. She leaves the party.
In the season finale, Blair is going to spend the summer in Monaco and Dan will spend time with Eric in the Hamptons. Louis has asked Blair to marry him, and she has accepted. Dan and Blair make plans to watch movies together, as friends, over Netflix.
link=http://gossipgirl.wikia.com/wiki/Season_5|frame|In the End...Season 5 of Gossip Girl begins with Dan in the Hamptons. He appears upset when he receives Blair's invitation for her royal wedding. Dan soon finds out that someone has published his book, Inside. Meanwhile, Blair, back from her cruise and is currently in Manhattan again, is frustrated with Louis' domineering mother, who feels the need to have complete control over the wedding. Dan finds out that Vanessa has published his book without his permission and tries to undo the damage, especially after Vanity Fair magazine want to publish a part about Dan and Blair.
Desperate, Dan turns to Louis for some help, hoping the prince could put some royal weight on it and manage to cancel the publishing. Louis informs him that he promised earlier to Blair that he's going to take her to the Royal consulate, so he calls her and tells her that he would not be able to make it, much to Blair's disappointment. Soon after, Blair then arrives at Dan's loft and tells him that despite they haven't spoken since the holidays, he is the only person she knows in New York at the moment. She announces that she plans to break it off with Louis. She asks him about his trip to the Hampton, to which he responds to staying at CeCe's house. She asks if he will take her to the Hampton as she will need to get away from the city after she ends things with Louis.She asks him to 'take her there' and Dan fools her into believing that Louis does not have her best interests at heart, despite the fact that Louis is doing something to help him. He begins to get ready just as Louis enters the loft. Blair assumes that Louis was following her, and starts reprimanding him. Dan's conscience gets the better of him and reveals that he tricked her, and the reason Louis was not there was because he was helping Dan with his book issue. Blair soon becomes furious with Dan as he did not tell her the real reason why Louis could not make it and departs with Louis, arm-in-arm, leaving Dan alone. And at the end of the episode it's been revealed that Blair is the one pregnant.
Over the next few episodes, Blair is found having trouble keeping the pregnancy a secret and begins having morning sickness. Things get more difficult when Louis's sister, Princess Beatrice, comes to town. When she hears Blair's morning sickness in the bathroom, she begins to assume that Blair has gone back to being bulimic. She decides to invite Blair to a feast to be sure.
Meanwhile, in Brooklyn, Dan is still trying to stop the publishing of his book, so that he will not be rejected by his closest friends and family. He calls Serena on the phone and asks her how she went through Lily's bank account so that he can go to Vanessa's bank and look for the publisher, but she tells him that it was all Chuck's doing, driving him to go searching for Chuck. To his horror, he finds Chuck getting beaten up by a group of men. He attempts to stop the men unsuccessfully, but when Chuck tells them to stop, he reveals that the men were not real criminals and he paid them to hurt him, much to Dan's astonishment. This leads Dan to search for Blair and inform her about Chuck's recent dilemma so that he get him the helps that he wants.
Meanwhile, at the feast, Blair begins to feel sick and searches for an excuse to run to the bathroom without arising suspicion. She begins to silently pray to God for a way out, and once she finishes, she sees Dan at the front of the door. Blair drags him to the toilet and orders him to guard the door. Dan announces that Chuck is getting himself into trouble again, but Blair brushes it off, stating that he's merely doing it to get her attention.
Once Dan hears Blair throw up, he begins wonders what is wrong with her and, like Beatrice, assumes that she has gone back to her previous bulimic ways. He voices out his concern and Blair leaves the wash-room stall, stating that she was not bulimic, but instead pregnant. However, Beatrice walks into the bathroom just as Blair reveals her pregnancy to Dan. The both of them are shocked, but agree to keep it a secret.
Afterwards, Blair arrives at Dan's loft once again, revealing to him that she is uncertain who the father of her unborn child is. He encourages her to take a test, but she refuses, stating that she'll lose her fairytale if Chuck is the actual father. Dan responds that she will still have him. However, Blair, being her usual self, still tries to avoid taking the test, but after much persuasion from Dan, she eventually does, and announces that the father is Louis. She then tells Louis that she's pregnant, much to his elation. Soon afterwards, Serena, Nate, Chuck, Louis's mother, Eleanor and Cyrus all know about Blair's pregnancy, and she decides not to keep anymore secrets regarding her unborn child. Dan decides that it is time for him to tell Blair about his feelings for her, unrequited or not, when she comes and visits him at his loft, feeling heavy-hearted and dejected. She tells him that she wishes to be happy again, but has forgotten how to be.
After a very emotional phone call with Chuck, Blair enters Dan's living room heartbroken, looking devastated and emotionally drained. Dan decides to attempt and bring Chuck and Blair together again, as this is what Blair wants. He decides to keep his feelings for Blair quiet and bottled up, only letting Serena know how he feels about her. Dan leads both Chuck and Blair individually into an enclosed candlelight room. Once they both come face-to-face, Dan closes the door and shows himself out, leaving them both alone. Then, he engages in a discussion with Serena, telling her that it would be wrong to him to reveal his feelings about Blair to her. Serena to tells him that he's one of the good guys.
While Blair and Chuck are whisked away in a town car, planning on running away together, Blair decides that she wants to raise her unborn child with Chuck. They both end up in a serious, life-threatening car accident when paparazzi tail them continuously after Ivy sends Gossip Girl a blast, informing her on Chuck and Blair's whereabouts. The accident causes Serena, who is alongside Nate and Dan, to be more furious at Gossip Girl then ever before, and blames her entirely for the accident caused. Dan momentously states that she (Gossip Girl) didn't jump on one of the motorcycles and chase Chuck and Blair down the road, but Serena angrily responds that the accident is merely the result of all the amount of damage that Gossip Girl has caused throughout the years. Nate agrees, and he Serena begin planning on taking Gossip Girl down for good, to avenge Chuck and Blair.
In the next episode, Blair learns that she lost the baby in the accident, much to her depression and despair, and she immediately bursts into tears when the news reaches her. She becomes even more terrified when Serena tells her that Chuck is in serious danger, due to losing a large amount of blood. This drives her to make a secret deal with God, promising Him that if he saves Chuck's life, she would marry Louis and not go back to being with Chuck. Once she makes the promise, the nurse informs her that Chuck is asking for her. She decides that this means that God has honored their promise, and chooses to further her relationship with Louis, so that Chuck will be safe, as she couldn't bare losing him.
She informs Dan about her deal and tells him to keep it a secret, to which he agrees, so that he will get to spend more time with her. Soon, only Dan and Serena know about Blair's promise. She begins avoiding Chuck and Louis, who collaborate to find out what was going on with Blair, and find pictures of Dan and Blair together in New York, learning that the only man she's not avoiding is Dan Humphrey.
Dan goes with Blair to her wedding dress fitting, and she gets upset due to the fact the the dress shows everything she has lost. Dan tells her that she should change her mind about marrying Louis, but she insists on pursuing the wedding, stating that she is committed to him.
Both Louis and Chuck think that Blair must be having an affair with Dan, as this is why she is so distant with everyone but him. They worry about her, and when asked if she is indeed having an affair with Dan, she immediately denies.
Soon later, she finds Louis's wedding vows, and is pleasantly stunned with how accurately he describes her and how much love the vows display. She tells Serena that she feels as if Louis had "Peered into her Soul", and now is happy with the decision she had made, believing that Louis is the one for her.
During the wedding day, Chuck and Blair confront each other once again, and Blair declares that she does indeed love him, she loves him more and more everyday, but cannot be with him. She leaves the room to attend the ceremony, leaving Chuck alone in the room. Cyrus and Harold both give Blair away, and Dan and Serena walk down the aisle together. However, it appears that Georgina has taped a Chuck and Blair's moment, when Blair was professing her love for Chuck. It was assued that Chuck was in possession of the videotape that was sent to Gossip Girl. It sends Blair running down the aisle, first wrongly accusing Chuck of sending the blast in that ruined her perfect day. She explains to Chuck that although she loves him she cannot be with him due to the pact she made with God. Louis appears at the door, and Blair apologizes for embarrassing him, returning to the alter soon after to continue the wedding. After Louis and Blair say their vows and take each other as man and wife, Serena tells Dan that she loves him, that she always had and she always will, just before Louis and Blair take their first dance as a married couple. As Blair tells Louis that she's very thankful for giving her a princess title and especially grateful that he gave her another chance, he coldly responds that their wedding was all for show and there is nothing but a contract between them. He tells her that when they're alone, they'll become like strangers to each other.
Blair calls Dan and tells him to pick her up outside the venue. Blair tells him that the wedding was a sham and she asks him for help to get out of the country and file for a divorce. Dan once accuses Chuck of sending in the video of the two as he tries to help Blair think of the best escape route. It is later revealed that Dan was in fact the one who sent in the video that ruined her wedding. Taking her to the airport, Dan realizes just how much she needs to get out of this situation and lies to Serena about her whereabouts.
After a scare at the airport, Dan takes Blair to a run-down hotel in Queens, where they have an argument and Dan gets annoyed at Blair for her constant complaining and insulting of him when he is just trying to help her. Chuck and Serena arrive, and Serena is hurt that Dan did not tell her about Blair running out of her wedding. Blair responds, saying that she could have told Serena as she is her best friend.
Louis' mother arrives, announcing that if Blair defaults in her marriage the dowry will be reinstated. Chuck tells Blair that he will pay the dowry, he would do anything for her if it meant she could be free. She then tells Chuck that she doesn't want this, as it would mean that they would not be equals when they got back together. She tells Chuck to wait a year while she is with Louis.
Soon afterwards, Blair arrives from her honeymoon to Manhattan on Valentine's Day. After speaking to both Serena and Dan, she realizes that the two of them have not had an enjoyable valentines day since they were both together. Blair decides that she will set Dan and Serena up once again.
Nate is planning on holding a Valentine's Day party where the guests dress as their high school selves. Dan is not planning on going, but when he gets a text from gossip girl saying that if he does not take Blair to the party, she will release the fact that Dan sent in the video of Blair and Chuck at the wedding.
Blair tries to set Dan and Serena up at the party, but when she notices the lack of interest Dan has in pursuing his old relationship with Serena. She tells him that she attempted to get Dan and Serena back together because she thought it was what he wanted. Blair asks him what it is that would make him happy, and he responds by kissing her, leaving Blair stunned. Serena, alongside Georgina, accidentally intrude on Dan and Blair. Georgina manages to snap a picture of Dan and Blair's kiss and soon runs away from the scene, driving Dan to chase after her, leaving Blair and stunned and angered Serena alone together. Blair continues to deny having any feelings for Dan during and after the party to both Dan and Serena.
With Serena and Blair's friendship on shaky grounds, Dorota decides to lock them in the dining room up for their own good. Blair decides to prove to Serena by spending a whole day with Dan that her feelings are platonic. Unfortunately, she reciprocates another kiss from Dan while Serena accidentally intrudes on them. Serena dictates that Blair is always in denial when it comes to matters of the heart. During a re-enactment of a scene from the Inside novel, Blair realizes that Dan loves her for her and has so for some time. Putting aside her insecurities she admits to both Serena and Dan that she too has feelings for Dan. Serena then gives Blair her blessing, stating that she does not want to be an obstacle in Dan and Blair's relationship. Soon afterwards, Blair pecks a kiss from Dan and heads off to support Serena with her last moments with CeCe.
Dan walks in on Blairdiscussing what could be a potential way out of her prenuptial agreement on the phone with Cyrus and another lawyer from his firm. At Cece's wake Chuck outs Dan via Gossip Girl as the sender of the video that was fatal to Blair's marriage. At first, she thinks that it's just a game Chuck is playing and she is unwilling to participate, however, when she sees the guilty looks on Dan's face she realizes that it's the truth. She is mad at him, but forgives him after he tells her that his only reason for sending the video was that he couldn't stand to see Blair so unhappy. Meanwhile, Blair makes a deal with Estee to help her get out of her marital dowry if there will be no more public mention of it in the media, including Gossip Girl. However, at this time Georgina, who has stolen Dan's phone, teams up with Chuck and sends Gossip Girl a message from Dan's phone uploading the photo of the Valentine's Day kiss, thus ruining Blair's chances of not having to pay the dowry. Dorota shows Blair the blast and she confronts Dan who is confronting Georgina. The latter admits to having been Gossip Girl and it turns out that the deal with Estee was also one of her schemes.
Dan goes to confront Chuck, who, after finding out that the blast will bankrupt Blair's family, is regretful, however, he reveals that he has outed Dan for the bad guy he has been and he question whether their friendship was just an act. Blair walks over to them and Chuck tells Dan to be honest and confess that he has been trying to keep him and Blair apart, which Dan does. He apologizes to Blair and leaves. Chuck says that he wants to be with Blair again because all the obstacles that were in their relationship's way are seemingly gone, but Blair tells him that although she loves him, she is not in love with him right now, at least not the way he needs her to be. Later Georgina visits Blair and promises to get her rid of her dowry in exchange for Blair's later support. Blair agrees to this.
In last scene of the episode Blair goes to Brooklyn. Dan isn't expecting her, as he is assuming she got back together with Chuck. Blair tells him that she isn't there to tell him off and she isn't with Chuck. She tells him that he has her heart. They start to kiss.In a series of unfortunate events... Blair and Dan have been unable to consummate their relationship for the past month; mainly due to the Dowry not being resolved resulting in no public displays of affections. Eventually, the solution comes from borrowing a hotel room from Lily and Rufus. Unfortunately, Blair and Dan are underwhelmed when experiencing that the sex was bad. Dan jokes to Nate that sex was bad because it was the same with him. Blair goes to Dorota for advice. They each dissect the various possible excuses but the only conclusion to be drawn is to be just honest. Later in the day Dan and Blair meet with each other at the foyer of Ivy's party while being intoxicated. In the long trip on the elevator the cumulating of both honesty and verbal taunts leads them to have sex in the elevator.
They end their day by going to a Brooklyn restaurant and then having sex in an alleyway.
Blair decides that she is not sure that she wants to sign her divorce papers as she is worried that she is giving something up that she is not ready yet. As she says this, Chuck appears in her penthouse. He asks Blair for advice as he is tracking down his mother. He dismisses him by telling him that they were never good as friends. Dan is anxious when he finds out that Chuck has paid Blair's dowry, as he thinks Blair will want to be with Chuck. Blair confronts Chuck about the dowry saying that Chuck wants to buy her again. Chuck in confused and says that he just wanted her to be free and with that freedom she can be with anyone she wants. Chuck leaves. Blair is about to follow him but Dan comes to apologize.
In the final scene Dan presents her with a tiara on the Met steps and tells her that she can be a princess one last time.
In the next episode, Blair and Dan are having trouble merging their worlds. Dan refuses to become an Upper East Sider and Blair refuses to become a Brooklyn girl. While they are at a eatery when they are overheard by the proprietors of the Oracle Club. They share their advice on merging worlds by suggesting Dan and Blair host a 'Kitch.' They decide to hold a salon, 'British themed' party, complete with pictures of her majesty herself on the wall. Dan and Blair decide not to invite any of their friends due to possible embarrassment, and instead are content on inviting various pseudo intellectual people that they have never met instead. At the party, Serena, Lola, Nate and Chuck all crash party. Blair becomes insecure, and whines to Dan about why their friends had to turn up at their 'coming out' party. Dan tells Blair that the night is about them, and to feel flattered that they would turn up. Blair and Dan have to help the kitchen staff so they leave halfway through their party, coming back to find all their pretentious guest leaving, claiming that the party was 'too dramatic'. Blair gets upset at Dan and says that if they can't fit into each others worlds, where does it leave them. Dan says 'I don't know' and Blair leaves.
Later that night, Dan turns up at Blair's penthouse. He apologizes to Blair and tells her that they are a team. They then have a sleepover and argue about Damien Hirst.
In the next episode, Blair is upset upon finding that Dan has received appraisal for his book in a magazine, whereas she has been labelled despicabledue to the fact that Kim Kardashian's marriage lasted longer than hers. Dan is attending a Simon & Schuster party where he will make a speech, and Blair decides that she wants to become 'high-brow despicable', so she attempts to make the night all about her and embarrass Dan and ruin his speech. After the party when Dan asks if Blair is jealous because of his success and her failures, she denies it, telling him that she can't remember who she is and needs help finding herself. Dan replies by saying that the 'Real Blair Waldorf' is closer than she thinks. They end the night with a hug.
In the morning, while Dan is dressing, both he and Blair discuss their respective mental blocks for the day. Blair aims to reclaim a bit of her original self. Dan is suffering from writers block for his second book and has a meeting with Alexandria. They say that they trust each other with the freedom to do whatever they want while going on separate ways. In Dan's meeting with Alexandria she attributes Dan's block for falling for his muse and arranges a surprise meeting for inspiration. Blair is asked by Chuck to aid in the pursuit of discovering his true paternity. Initially hesitant she receives a text from Dan cancelling their lunch plans. At the second meeting with a woman named Lucia, Dan receives an exclusive fellowship to attend the Arts and Letters institute at Rome. Apprehensive that his leaving will negatively affect his relationship with Blair he calls her midway during her scheme, but he feels unconvinced with her willingness to support this venture; especially with her proximity to Chuck. During a honest conversation with Rufus, Dan admits that he feels insecure because neither he, nor Blair, have yet to say 'ILY' (I love you). Walking past Chuck and Blair getting inside of a limo, a jumpy Dan follows them to a huge mansion. Upon returning back to the loft Dan makes an impromptu decision to cancel the retreat. When Blair returns to Dan he lies that a better candidate was found for the retreat. Blair apologises if her outing might have upset Dan and slowly begins to explains her trip to the brothel. Feeling appeased with Blair's honesty he says "I Love You," but quickly feels dejected when expecting a mutual response.
In the next episode, Blair receives a call from Alexandria in the morning about the unbeknownst cancelled trip to Rome and she wants Dan to reconsider. When Dan exits from the shower, Blair confronts his lie, to which Dan admits the truth about his insecurity. Blair slowly tries to persuade Dan to re-apply for the fellowship.
Confused about her feeling for Dan and Chuck, Blair agrees to go with Chuck when he needs her help to rescue his father. Serena calls Blair that Dan has some good news and Blair has to come right away. Apparently, the good news comes in the form of an accommodation for two, with a Blair less than please with spending a summer at Rome, but requires a vetting interview to approve additional guests. On a p.one call, Serena surmises that Blair is reluctant to go Rome because of Chuck, but Blair does not give an answer, instead she only stares at the tourist book. Shortly after she agrees to go on the trip with Dan. While preparing for the interview Blair receives a text from Chuck that she is needed and thus provides a weak cover to excuse herself. The interview is a success with the help of a proxy 'Blair' from Serena with Dorota's help. Later, Serena lets slip that Blair's reasoning for being with Chuck is due to helping Bart out. During tea time, Serena asks Blair that maybe it's time Blair told Dan how she feels. Blair confides to Serena that she is not ready to reciprocate Dan's feelings and wants the next I love you to be the last. Even so, she still agrees to go with Dan's Roman Trip.
Shortly afterwards an official Gossip Girl blast details an extract from Blair's Diary entry shortly before Dan told her he loved her and alludes to Blair's other concealed feelings at the time. Blair is horrified with its implications. Dan gives Blair an ultimatum, She has to choose, him or Chuck.
Blair makes her choice and chooses Chuck over Dan. The season ends with them on the outs, Dan is bitter and avoiding all contact with Blair, he goes to Rome with Georgina, vowing to write a book exposing the Upper East-side for what it truly is.
Relations between Dan and Blair are tense. Dan is furious with Blair because she's with Chuck now. Later in the Season 6, Dan reunites with Serena forgetting all about Blair. Five years later, Dan and Blair rekindled their friendship and Dan is about to get married with Serena. Blair is also married with Chuck and they have a son named Henry.
- Dan about Blair: "She's best friends with this girl, Blair Waldorf. Who is basically everything I hate about the Upper East Side distilled into one 95-pound, doe-eyed, bon mot tossing, label-whoring package of girly evil."
- Dan to Blair: "You have to decide what's more important to you, keeping your pride and getting nothing, or taking a risk and maybe having everything."
- Dan: "No headbands in college."
- Dan to Blair: "Blair, say life has given you signs, and you're ignoring them because you're afraid of the things they need you to do. But, then you think --what if these signs are here for a reason and ignoring them just makes me a coward."
- Blair: "What do you mean, "no visitors"? I don't think you realize who we are. Dan: Who she thinks she is, is more like it. Look, I'm family. I'm Serena's brother— or, step-brother technically, which I do mostly try to put out of my mind seeing as we dated pretty seriously— Blair: Humphrey, they treat people in here for less serious complexes than that. Do you want to get committed?"
- Dan : "I do think you deserve to be with someone who makes you happy."
- Blair: "Follow my lead Humphrey, you're used to doing that."
- Blair: "They're all good men before something happens to them, S. Some of them stay good. No matter how they're treated."
- Dan (to Rufus): "Friendship can be used as an excuse, a cover, when there's something more that you don't want to admit, or too scared to explore." Dan: "No, no, I mean just the idea of that is just..." Rufus: "Scary." Dan: "I mean, we're not even friends, I swear."
- Gossip Girl: "Why does a frienship based off of fight, end in flight? They say we run from the things that truly scare us."
- Blair: "Dan and Blair. Individual entities. Two proper nouns separated by a conjunction." Dan:"Or a comma, if mentioned in a list." Blair:"Which is rare. Since we have nothing in common and are in fact, opposites." Dan: "The kind of opposites who do not attract. Blair: Most definitely not." Dan: "No." Blair: "The world just wasn't ready for a Humphrey-Waldorf friendship. It's been nice not being friends with you." Dan: "Let's not do it again some time."
- Dan: "I've been walking around the city all night with one all-consuming, paralyzing thought." Blair: "...why am I in the City when I live in Brooklyn?" Dan: "Blair, what if there is another reason we've been keeping us a secret." Blair: "Another reason like what?" Dan: "Plausible deniability. Blair, we've been keeping us a secret because we're afraid there is something more."
- Gossip Girl: "The question of whether we can fight fate will always remain a mystery." Gossip Girl: "But the bigger question is what happens when we stop fighting it."
- Eric: "Do you like her?" Dan: "What? No no no. I don't like her. No, of course not. Not at all. I'm just curious. And you know, I mean, she does... she does smell nice." Eric: "Oh, you are ass backwards crushing on Blair Waldorf!!!"
- Blair: "It's about the truth. Something happened recently that revealed my future and I've been hiding ever since 'cause I don't want to deal with it."
- Dan: "For someone who's just a friend, you're really good at choreographing reasons for us to kiss."
- Blair: "I'm really sorry, S. I guess I was in denial. I didn't want to admit that I'd begun to understand the Humphrey appeal." Serena: "The only appeal Dan ever had to you was that he was mine." Blair: "You would see it that way. Because it's always about you, isn't it? I'm sorry to break it to you but Dan and I have a real connection."
- Blair: "You were in the Hamptons?" Dan: "Ah, Amagansett. Cece's house." Blair: "Is it empty? Take me there."
- Gossip Girl: "Lonely Boy learning three words, eight letters don't come out right when no one wants to hear them."
- Dan: "If I didn't know any better, I'd think you're starting to like Brooklyn." Blair: "It isn't Brooklyn I'm here for. You're the only person I can have a furtive, emotionally-loaded conversation with right now."
- Gossip Girl: "Maybe it's not blood bonds that make us a family. Perhaps it's the people that know our secrets and love us anyway. So we can finally be ourselves. XOXO —Gossip Girl."
- Blair: "I turned to you, Dan. Because I knew you were the only one who would protect me from my own worst instincts."
- Dan: "Blair, I never wanted us to come between you two." Blair: "When are you going to get it through your head? There's no us! There never was. There's nothing here but friendship, and even that's gone now."
- Chuck: "It wasn't until I saw you confronting Blair, that I realized I had it all wrong." Dan: "Wait, had what wrong?" Chuck: "You're in love with her." Dan: "No, no, no...I'm...I'm not. I'm not in love...with Blair..."
- Blair: "You don't think it would matter that my baby is another man's child?" Dan: "It wouldn't to me."
- Dan: "You were right, I was going to tell Blair how I felt about her." Serena: " You mean you were going to tell her you love her." Dan: "Inspite of myself, and honestly, many times, inspite of her. I mean, I didn't want to. I keep trying make it go away, but how do you kill a feeling?"
- Blair (on "Claire" and "Dylan"): "If she ever had to kiss him, it would be perfunctory — like shaking someone’s hand, or petting a dog."
- Blair' (to Serena about Dan): I’ll point out the sadness of his hair, clothing, and Brooklyn roots, and he will decry my constructive criticism as snobbery. We’ll share our views on recent French cinema. And there will BE NO KISSING."
- Dan: "I don’t want to be your friend Blair. I want more, I want you, and if you don’t feel the same way about me then I don’t think we should be seeing each other any more."
- Blair: "Dan loves me for me."
- Blair: "One of my specialities is warped logic." Dan: "It is a unique skill you have." Blair: "It's awful." Dan: "It's not awful. It's you, it couldn't be awful." Blair (endearingly): "Humphrey..."
- Blair: "So, Dan, are you gonna invite me in or what? ... What?"
Dan: "You just said my name."
Dan: "Yeah. Can you say it again?"
Dan: "Say it again."
Blair: "Dan. Dan..."
- Dan: "I thought you should feel like a princess one last time."
- Dan (to Blair): "Maybe you are so focused on how everyone else perceives you that you no longer know who you are. And that’s too bad because if you could only see what I see."
- Blair: "Somehow between being traded for a hotel and selling out for a tiara, I lost my true self. But I want to be found. Could you possibly help?" Dan: "I have a feeling that the real Blair Waldorf is a lot closer than you think. It wasn't too long ago she and I were working side-by-side at W, and I completely fell for her." Blair: "And, what was that girl like?" Dan: "That girl is fiercely strong. Independent. Outspoken. Beautiful. Capable of anything...and no man or magazine should be able to take that away from her."
XOXO GOSSIP GIRL