A new diimide-diacid chloride (3) containing a noncoplanar 2,2'-dimethyl-4,4'-biphenylene unit was synthesized by treating 2,2'-dimethyl-4,4'-diamino-biphenylene with trimellitic anhydride followed by refluxing with thionyl chloride. Various new polyester-imide)s were prepared from 3 with different bisphenols by solution polycondensation in nitrobenzene using pyridine as hydrogen chloride quencher at 170degreesC. Inherent viscosities of the poly(esterimide)s were found to range between 0.31 and 0.35 dL g(-1). All of the polyester-imide)s, except the one containing pendent adamantyl group 5e, exhibited excellent solubility in he following solvents: N',N-dimethylformamide, tetrahydrofuran, tetrachloroethane, dimethyl sulfoxide, N,N-dimethylacetamide, N-methyl-2-pyrrolidinone, m-cresol, o-chlorophenol, and chloroform. The polymers showed glass-transition temperatures between 166 and 226degreesC. The 10% weight loss temperatures of the polyester-imide)s, measured by TGA, were found to be in the range between 415 and 456 C in nitrogen. (C) 2004 Wiley Periodicals, Inc.