An unsymmetrical and noncoplanar heterocyclic dianhydride was synthesized from a bisphenol-like phthalazinone, 4-(4-hydroxylphenyl)-2,3-phthalazin-1-one, and a series of novel poly(ether imide)s based on it, with intrinsic viscosities of 0.67-1.42 dL/g, were obtained by one-step solution polymerization in m-cresol at 200 degreesC for 20 h. The polymers were readily soluble in N-methyl-2-pyrrolidinone and m-cresol. The poly(ether imide)s derived from 4,4'-oxydianiline and 4,4'-methylenedianiline were also very soluble in chloroform, 1,1',2,2'-tetrachloroethane, and N,N-dimethylacetamide. The glass-transition temperatures were 289-326 degreesC, as determined by differential scanning calorimetry. All the degradation temperatures for 5% weight loss occurred above 482 degreesC in nitrogen. The tensile strength of thin films of some of the polymers varied from 103.1 to 121.4 MPa. (C) 2004 Wiley Periodicals, Inc.