Eight linear conjugated compounds have been synthesized by reacting terephthal-dehyde and glyoxal with aromatic diamines．The UV-Vis．spectra of the model com-pounds and their corresponding polymers revealed that the absorption bands shift toward the long-wave region as the degree of conjugation increases．It was shown from the structure of the condensation product of glyoxal and p-phenylene diamine that the aromatization occurs after heat-treatment．but in case of condensation of terephthaldhyde with p-phenylene diamine further polycondensation instead of aromatization took place during the heat-treatment below 350℃．Electric properties of the polymers depend not only on the degree of conjugation in molecules but also the structure between molecules．