An imide ring-containing dicarboxylic acid, 3,3-bis[4-trimellitimidophenoxy)phenyl]phthalide, was prepared by the condensation of 3,3-bis[4-(4-aminophenoxy)phenyl]phthalide and trimellitic anhydride. A series of new aromatic bis(phenoxy)phthalide-containing poly(amide-imide)s having inherent viscosities of 0.84-1.10 dl g(-1) were prepared by the direct polycondensation of this diimide-diacid with various aromatic diamines using triphenyl phosphite and pyridine as condensing agents in N-methyl-2-pyrrolidone (NMP) in the presence of calcium chloride. Most of the resulting polymers showed an amorphous nature and were readily soluble in polar solvents such as NMP and N,N-dimethylacetamide, All the soluble poly(amide-imide)s afforded transparent, flexible and tough films. The glass transition temperature of these polymers were in the range of 250-318 degrees C and showed almost no weight loss up to 450 degrees C under air or nitrogen atmosphere.