1 ,4-Bis(tert-butylthio)-3, 6-diphenylthieno[3, 4-c]thiophene (2a) and 1,4-bis(tert-butylthio)-3,6-di(2-thienyl)thieno[3,4-c]thiophene (2b) were synthesized from 2-tert-butylthio-3-phenylcyclopropenethione (1a) and 2-tert-butylthio-3-(2-thienyl)cyclopropenethione (1b), respectively, by treatment with triphenylphosphine in benzene.