does anyone know who the know robin. in the new movie dark knight.?

Answer 1

Robin is not in the Dark Knight. Nolan explained that he was not including Robin in the franchise because Christian Bale was still portraying a "young Batman", which meant Robin was "still in a crib somewhere".

On July 31, 2006, Warner Bros. Pictures officially announced the initiation of production for the sequel, titled The Dark Knight.

Cast

Christian Bale as Bruce Wayne / Batman: A billionaire who has dedicated himself to being the vigilante protector of Gotham City in the form of Batman, the Dark Knight.
Heath Ledger as The Joker: A criminal who has a "taste for theatrics" , and after committing a robbery and a double homicide at the end of the first movie, leaves a Joker playing card at the scene of the crime.
Gary Oldman as Lieutenant James Gordon: A member of the Gotham City Police Department who is one of the few uncorrupted officers in Gotham City.
Aaron Eckhart as Harvey Dent: The district attorney of Gotham City.
Michael Caine as Alfred Pennyworth: Bruce Wayne's trusted butler who tends to Wayne Manor.
Morgan Freeman as Lucius Fox: The recently-promoted CEO of Wayne Enterprises who had supplied Bruce Wayne with the gear necessary to carry out Batman's mission.
In July 2006, Warner Bros. Pictures announced that Christian Bale would reprise his role as Batman with Heath Ledger opposite Bale as the Joker.[4] Before Ledger was confirmed as the Joker, actors Paul Bettany,[5] Lachy Hulme,[6] Adrien Brody,[7] and Robin Williams[8] had publicly expressed interest in the role. In October 2006, Nolan revealed that Harvey Dent would make an appearance in The Dark Knight, though the character had yet to be cast at the time.[9] Actors Liev Schreiber,[10] Josh Lucas,[11] and Ryan Phillippe[12] had expressed interest in portraying Dent. In February 2007, actor Aaron Eckhart was cast as Harvey Dent.[13]

Cillian Murphy, who portrayed the Scarecrow in Batman Begins, said in an August 2005 interview that he was interested in returning, as he is contracted for possible sequels, but he did not know if he will reprise his role.[14] That same August, producer Charles Roven said that Katie Holmes, who portrayed Rachel Dawes in the film, was signed on for the sequel.[15] In an October 2006 interview, Nolan said that he hoped that Katie Holmes would come back, and the director indicated that he would contact other Batman Begins characters to return for The Dark Knight after he finished the script.[16] In January 2007, Holmes had turned down an offer to reprise her role as Rachel Dawes due to scheduling conflicts. The studio is currently seeking a new actress to portray the character.[17]

Nolan explained that he was not including Robin in the franchise because Christian Bale was still portraying a "young Batman", which meant Robin was "still in a crib somewhere".[18] In addition, Nolan considered the Penguin difficult to portray on film, explaining, "There are certain characters that are easier to mesh with the more real take on Batman we're doing."[19]
wikipedia.com

Answer 2

Internet Movie Database does not list Robin as a character.