A series of polyimides were synthesized from new diamine, Bis [4,4'-amino-5,5' trifluoromethyl phenoxy-(hexafluoro isopropylidine) phenoxy phenyl] benzonitrile [BATFB] and various aromatic tetracarboxylic anhydrides by thermal and chemical imidization routes. The BATFB was synthesized in two steps by nucleophilic displacement reaction of 2,6-dichloro benzonitrile, 4,4'(hexafluoro isopropylidine) diphenol and 2-amino-5-fluoro benzotrifluoride in the presence of anhydrous potassium carbonate in N,N'-dimethyl acetamide (DMAc) and the structure was confirmed by FTIR spectroscopy and CHNSO analyzer. The polymers were characterized by FTIR spectroscopy and thermal analysis were performed by differential scanning calorimetry and thermogravimetric analysis methods. The prepared polyimides had glass transition temperatures between 230 and 290 degrees C and their 10% weight loss were recorded in the range 550-590 degrees C in N-2 atmosphere. Majority of polymers are found to be soluble in most of the organic solvents such as DMSO, DMF, DMAc, in-cresol, and THF even at room temperature and few becomes soluble on heating. The prepared polyimides showed water uptake values 0.34-0.54 wt% at room temperature. (c) 2006 Wiley Periodicals, Inc.