The optical properties of poly [oxyisophthaloyloxy-(2-methoxy-p-phenylene methylidene-(2-oxo-1, 3-cyclohexanediylidene) methylidyne-(3-methoxy-p-phenylene)](I) and poly [oxysebacoyloxy-(2-methoxy-p-phenylene) methylidene-(2-oxo-1, 3-cyclohexanediylidene) methylidene-(3-methoxy-p-phenylene)](II) polymer films were studied. The transmission and absorption measurements were carried out in the energy range 1.9–3.2 eV at 300 K. The data on absorption coefficient versus photon energy were analysed and interpreted in terms of the Tauc model,(α h ̵ ω) 1 2= B 1 2 (h ̵ ω− E opt g). Analysis of experimental results shows that the absorption characteristics give a good fit to the Tauc model, and indicates that both polymers I and II have an indirect band gap. The values of the optical gap E opt g and the slope of the Tauc plots B 1 2 were determined. The study shows that the indirect allowed optical …