The electrochemical and spectroelectrochemical redox behaviour of two different monomers, suitable for non-linear optical applications, 3-[6-(4-oxy-4′-nitrostilbene)hexyl]thiophene and 3-{6-[4-(4′-nitrophenyl-azo)phenoxy]hexyl}thiophene, are investigated by cyclic voltammetry. In addition the suitable conditions for an electrochemical synthesis of the homopolymer and copolymer with some alkylthiophenes (3-methylthiophene and 3-hexylthiophene) are studied. The polymeric films obtained are characterised by electrochemical methods, spectroelectrochemical UV–vis–NIR and FT-IR in reflectance and compared with the polymer obtained by a chemical method, cast onto Pt and ITO glass surfaces.