The it-electron delocalisation in conjugated thienylenevinylenes bearing arylethenyl chromophores, makes those materials interesting candidates for electro-optic applications. In this study, we report the results of electrochemical and UV-Vis/ESR spectroelectrochemical studies of a pair of thienylenevinylenes substituted by the 4-cyanostyryl group, bearing either a hydrogen, or methyl group terminated a carbons at the peripheral thiophene rings. The reactivity of various functional segments of investigated molecules was assessed by comparing the reactivity of the protected and unprotected counterparts and the behaviour of their electrooxidation products. For the capped derivative, two irreversible anodic redox processes giving electrochemically inactive products were observed, while the uncapped molecule yields electroactive materials already upon its first oxidation step. (c) 2011 Elsevier Ltd. All rights reserved.