A novel fluorinated aromatic diamine, bis[4-(40-aminophenoxy)phenyl]-3,5-bis(trifluoromethyl)-

phenyl phosphine oxide, was synthesized. A series of new fluorinated polyimides containing phosphine oxide was prepared from the novel diamine with various commercially available aromatic dianhydrides. All the fluorinated polyimides show high glass transition temperatures, excellent thermal stability, and good solubilityin common organic solvents.