Résumé : The synthesis and characterization of two new anthradithiophene (ADT) derivatives substituted by thiophenyl or 2-octylthiophenyl units at the 5,11-positions and donor (triphenylamine) or acceptor (aldehyde functions) moieties at the 2,8-positions of their backbone are described. Optical measurements were performed to evaluate the effect of electron-rich/-poor substituents on their stability towards photo-oxidation and were supported by quantum chemical calculations and cyclic voltammetry experiments. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.