Copolymer of thiophen-3-yl acetic acid 4-pyrrol-1-yl phenyl ester (TAPE) with N-methylpyrrole (NMPy) was synthesized by potentiostatic electrochemical polymerization in acetotiitrile-tetrabutylammonium tetrafluoroborate solvent-electrolyte couple. The chemical structures were confirmed via Fourier transform infrared spectroscopy (FTIR), cyclic voltammetry (CV), and UV-vis spectroscopy. Electrochromic and spectroelectrochemical properties of poly(TAPE-co-NMPy) [P(TAPE-co-NMPy)] were investigated. Results showed that the copolymer revealed color change between light yellow and green upon doping and dedoping of the copolymer, with a moderate switching time. Furthermore, as an application, dual-type absorptive/transmissive polymer electrochromic device (ECD) based on poly(TAPE-co-NMPy) and poly (3,4-ethylene dioxythiophene) (PEDOT) have been assembled, where spectroelectrochemistry, switching ability, stability, and optical memory of the ECD were investigated. Results showed that the device exhibited good optical memory and stability with moderate switching time. (c) 2006 Wiley Periodicals, Inc.