Dual type polymer electrochromic devices (ECDs) based on poly(terepthalic acid bis-(2-thiophen-3-yl-ethyl)ester) (PTATE), its copolymer with thiophene P(TATE-co-Th) and poly(3,4-ethylenedioxythiophene) (PEDOT) have been constructed. Spectroelectrochemistry, switching ability and stability of the devices were investigated by UV-Vis Spectrophotometer and Cyclic voltammetry. These devices exhibit low switching voltages (between 0.0 V and +1.6 V), short switching times with reasonable switching stability under atmospheric conditions.