Film Details:
Here is more information about the costume and how it informs the character:
Similar to his colorful suit in New York, New York, Bob uses bright, boldly-hued clothes to demonstrate the relentless nature of a determined, selfish character- this time Rupert Pupkin, who keeps coming back again and again to Jerry Langford’s office to secure a spot on the show. When the receptionists turn him away again and again, Rupert resorts to kidnapping Jerry. Given his own delusions of fame and talent, and his inability to accept reality, the bright colors don’t seem out of place in Rupert’s wardrobe.
Did you know? Scorsese said that he and Bob may have not worked together again for seven years because of the emotionally grueling nature of making this film. Additionally, Scorsese later admitted that making this film was an "unsettling" experience, in part because of the embarrassing, bitter material of the script. (via IMDb)