Access to the title compounds (12–14) was achieved by two different syntheses starting from either phenylacetylene (1) or, from benzo [b] thiophene (2) by a reaction sequence formally equivalent to the insertion of sulfur. The key intermediates in both routes are the (Z, Z)- styrene-1, 4-dithiol derivatives4–6 and9–11, respectively. Compared with monocyclic 1, 2- dithiins, the absorption maxima of compounds12–14 occur at shorter wavelengths and ...
