[reaction: see text] A series of bay position difluoro- or tetrafluoro-substituted perylene bisimides have been synthesized by nucleophilic halogen exchange reaction of the corresponding dibromo- and tetrachloro-substituted perylene bisimides, respectively, with potassium fluoride. Compared to the parent unsubstituted perylene bisimides, these compounds display hypsochromically shifted absorption and fluorescence spectra with fluorescence quantum yields up to unity enabling bright yellow emission. Their electrochemical properties and crystal structures of two perylene bisimides are also reported.