A series of fluorinated polyamideimides (PAIs) were synthesized by the direct polycondensation of a novel diimide-diacid, 1,4-bis(trimellitimido-2-trifluoromethylphenoxy) benzene (BTTFB), with aromatic diamines by using triphenyl phosphite (TPP) and pyridine as condensation agents in a medium consisting of N-methyl-2-pyrrolidone (NMP) and CaCl2. Most of the resulting polymers showed an amorphous nature. All the fluorinated PAIs were readily, soluble in a variety of organic solvents such as NMP, N,N-dimethyl acetamide, dimethylformamide, and dimethyl sulfoxide and could even be dissolved in less polar solvents such as THF and m-cresol. The PAIs had inherent viscosities of 0.77-0.93 dL/g, depending on the diamines. All the soluble PAIs afforded transparent, flexible, and tough films that exhibited excellent thermal stability, good mechanical properties, and low moisture absorption. The glass transition temperatures of these PAIs ranged from 244 to 272degreesC and the 5% weight loss temperatures were >525degreesC in nitrogen. (C) 2004 Wiley Periodicals, Inc.