Ferrocene-substituted conducting polymer namely poly(trans-1-(4-methyl-3'-thienyl)-2-(ferrocenyl)ethene-co-3,4-ethylenedioxythiophene) [P(MTFE-co-EDOT)] was synthesized and its electrochromic properties were studied. Monomer, MTFE, was obtained using 2-(ferrocenyl)ethene and 3-methyl-4-bromothiophene. The structure of monomer was determined via Fourier transform infrared spectroscopy (FTIR), 1H-NMR, and 13C-NMR techniques. The copolymer was synthesized using this monomer and EDOT. The resulting copolymer P(MTFE-co-EDOT) was characterized by cyclic voltammetry, FTIR, scanning electron microscopy, atomic force microscopy, and UVvis spectroscopy. The conductivity measurements of copolymer and PEDOT were accomplished by the four-probe technique. Although poly(trans-1-(4-methyl-3'-thienyl)-2-(ferrocenyl)ethene) [P(MTFE)] reveals no electrochromic activity, its copolymer with EDOT has two different colors (violet and gray). Band gap (Eg) and ?max of P(MTFE-co-EDOT) were determined. (c) 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012