A cyclic octithiophene containing β,β'-linkages.

A cyclic octithiophene containing two β,β'-linkages was synthesized. Due to the large structural change in the excited state, this compound exhibited bathochromically shifted fluorescence. It also showed a small difference between the first and second oxidation potentials, indicative of spin delocalization through the β,β'-linkage in the one electron-oxidized state.