Electroactive conducting copolymers of aniline (ANI) and ethyl 4-aminobenzoate (EAB) were prepared electrochemically. Cyclic voltammetric studies were carried out with different feed concentration of EAB on glassy carbon electrode surface. The voltammograms exhibited different behavior for different concentrations of EAB. The copolymers exhibited high solubility in many polar solvents. The scan rate exerted good influence on the polymer effect on this GCE copolymer film, revealing electroactive film's excellent adherent properties. The effect of pH on the copolymer film showed that the polymer was electrochemically active up to pH 7.0. Spectroelectrochemical analysis of the copolymer film, carried out on an indium tin oxide (ITO) plate, showed multicolor electrochromic behavior when the applied potential was changed. The color of the copolymer was changed from neutral yellow (422 nm) to green (760 nm) and to blue (600 nm) at the concentration of 0.1 M aniline and 0.1 M EAB in 0.1 M H2SO4 medium. The copolymer was characterized by FT-IR spectral data. The surface morphology were studied using SEM and TEM analysis. The grain size of the copolymer was measured using XRD studies and was found to be 80 nm. The electrical conductivity of the copolymer was 3.21 x 10(-2) S cm(-1), as determined using a four-probe conductivity meter. (C) 2011 Elsevier Ltd. All rights reserved.