Synthesis and characterization of dimers, trimers, and tetramers of 3,6-dimethylthieno[3,2b]thiophene and 3,6-dimethylselenolo[3,2b]selenophene

3,6-Dimethylthieno[3,2-b]thiophene (1a) and 3,6-dimethylselenolo[3,2-b]selenophene (1b) have recently become readily obtainable. Starting from these compounds, their dimers, trimers, and tetramers, in which each thienothiophene unit and selenoloselenophene unit were regularly connected at their alpha-position, were satisfactorily synthesized and characterized by UV/Vis spectral and CV oxidation potentials data. X-Ray single crystal structure analysis of the dimer of 1b revealed that two selenoloselenophene units are twisted with a large dihedral angle of 69.5 degrees with an s-cis structure.