short answer: Batman "fired" him for his own well-being.
longer answer:
Dick enjoys his first year as Robin, regarding the job as an adventure until a confrontation with Two-Face serves as a rude awakening for the young hero. The villain captures Judge Lawrence Watkins (previously version of the story was Gotham's newly elected district attorney Aldrich Meany[1]) and Batman, and has each suspended from a hangman's noose in a "double gallows death-trap". Robin, trying to save the judge, convinces Two-Face to flip his trademark coin on whether or not Watkins would hang. Robin wins the flip, but Two-Face "honors" the deal by drowning the judge instead. Robin is unable to prevent Watkins' death, and receives a beating at the hands of Two-Face; a beating that Batman witnesses, still tied up on the platform. Eventually, Batman frees himself and apprehends the villain. This event, however, emotionally scars the young crime-fighter. Rather than see Dick be further endangered, Batman "fires" his partner, sidelining the 13-year-old Boy Wonder for a while, only to bring him back shortly afterwards. Four years later, when Dick is 17, he is shot in the shoulder by the Joker, which scares Batman into finally ending Robin's career as his partner. Seeking emancipation, Dick moves out of the mansion and joins the Teen Titans full-time.
http://en.wikipedia.org/wiki/Publication...
Cuz Batman wasn't "swish" and Dickie-boy couldn't handle the rejection.
They were gay lovers, and had a spat and broke up.
Yeah, he voluntarily quit being Robin to become his own person, defending Bludhaven as Nightwing.
my friend said it was cause batman "fired" him i thought it was cause he was sick of being in batman's shadow which is it
