A new class of unsaturated polyesters of diarylidenecycloalkanones con taining the azomethine group in the polymer backbone has been prepared. Synthesis involved the interfacial polycondensation of 4,4'-[1,4-phenylene bis (methylidynenitrilo)] dibenzoyl chloride II with 2,5-bis(p-hydroxybertzylidene) cyclopentanone III, 2,5-di vanillylidenecyclopentanone IV, 2,6-bis(p-hydroxybenzylidene) cyclohexanone V or 2,6- divanillylidenecyclohexanone VI at ambient temperature. The resulting polyesters were characterized by elemental analyses, IR spectroscopy, solubility and viscometry measure ments. The thermal properties of the polymers were evaluated by thermogravimetric analysis and differential thermal analysis measurements and correlated to their structu ral units. The crystallinity of all polymers was examined by X-ray analysis. In addition, the electrical properties of all polyesters were measured.