Three compositionally different copolymers derived from N-vinylcarbazole and N-phenyl-2-(5＇-vinyl-2＇-thienyl)-5-(2"-thienyl)-pyrrole were synthesised chemically and characterised. The composition of the copolymers was estimated using FT-IR spectroscopy and in situ spectroelectrochemistry and spectrocolorimetric measurements were performed on the solid state electrochromic devices fabricated using these copolymers as working electrodes. The colour contrasts of these devices in both the neutral and the doped states were measured by spectrocolorimetry conforming to the Commission International de 1＇Eclairage (CIE) methods. The CIE colour coordinate values in the p-doped state of the devices could be correlated to the comonomer ratios in these copolymers.