A new class of unsaturated polyesters based on diethylketone have been prepared by interfacial polymerization of 2,4-bis(4-hydroxybenzylidene)-3-pentanone(I) and 2,4-bis(4-hydroxy-3-methoxybenzylidene)-3-pentanone(II) with 4,4’-azodibenzoyl chloride and 3,3’-azodibenzoyl chloride at ambient temperature. The model compounds were synthesized by reaction of(I) and(II) with benzoyl chloride. The new monomers, model compounds and polyesters have been characterized by different spectral analyses. The polyesters have inherent viscosity of 0.55-0.80 d L/g and moderate number average molecular weight(Mn) in the range of 6150-7400 g/mol. Most of the compounds exhibited their solubility in aprotic solvents while partial solubility in various halogenated organic solvents was observed. The temperatures of 10% weight loss were high(225-330 °C) in nitrogen, indicating that these polyesters have excellent thermal stability. Doping with iodine dramatically raised the conductivity and produced brown colored semiconductive polymers with a maximum conductivity of 2.7 × 10-6 --1cm-1. Moreover, the morphological properties of selected example of polyesters were detected by SEM. A new class of unsaturated polyesters based on diethylketone have been prepared by interfacial polymerization of 2,4-bis (4-hydroxybenzylidene) -3-pentanone (I) and 2,4-bis -pentanone (II) with 4,4’-azodibenzoyl chloride and 3,3’-azodibenzoyl chloride at ambient temperature. The new compounds, model compounds were synthesized by reaction of (I) and (II) with benzoyl chloride. and polyesters have been characterized by different spectral analyzes. The polyesters have an inherent viscosity of 0.55-0.80 dL / g and moderate number average molecular weight (Mn) in the range of 6150-7400 g / mol. Most of the compounds exhibits their solubility In aprotic solvents while partial solubility in various halogenated organic solvents was observed. The temperatures of 10% weight loss were high (225-330 ° C) in nitrogen, indicating that these polyesters have excellent thermal stability. Doping with iodine dramatically raised the conductivity and produced brown co lored semiconductive polymers with a maximum conductivity of 2.7 x 10-6 - 1 cm-1. Furthermore, the morphological properties of selected examples of polyesters were detected by SEM.