Polystyrene (PS) functionalized carbazole macromonomer was synthesized and polymerized by electrochemical oxidative polymerization on the ITO-glass surface. The structure of the macromonomer was elucidated by (1)H NMR, FT-IR, UV-Vis and cyclic voltammetry (CV). The spectro-electrochemical and electrochromic properties of the polymer film were investigated. Also the greenish blue colored film converted to dark blue color by the applying potential. Polystyrene-carbazole/polyethylenedioxythiophene (PS-Carb/PEDOT) electrochromic device was assembled in sandwich configuration: ITO-coated glass/anodically coloring polymer (PS-Carb)//gel electrolyte//cathodically coloring polymer (PEDOT)/ITO-coated glass. According to kinetic studies of this device, the optical contrast Delta T% at 640 nm between -1.0 and +2.0V with a residence time of 10s was found to be 38% and switching time was measured as 1.1s. (C) 2009 Elsevier B.V. All rights reserved.