We report here on the synthesis and properties of a monosubstituted quaterthiophene derivative asymmetrically functionalized by an electron-withdrawing group using the palladium-catalyzed Stille's coupling reaction. The UV-vis absorption spectrum evidences a strong intramolecular charge transfer transition. Thus oligothiophenes act as electron donors and substituent group as acceptor. The diodes in which monosubstituted quaterthiophenes behave as organic semiconductors, exhibit a rectifying behavior. Photovoltaic measurements show moderate power conversion efficiency. (c) 2005 Elsevier B.V. All rights reserved.