New dithienothiophene donors for cation radical salts

New methylthio substituted dithienothiophenes, 2,2′-bis(methylthio)dithieno(4,5-b:5′,4′-d)thiophene 2, 2,2′-bis(methylthio)- 3,3′-dibromodithieno(4,5-b:5′,4′-d)thiophene 3, 2,3,2′,3′-tetrakis(methylthio)dithieno(4,5-b:5′,4′-d)thiophene 4 and 2,5,2′,5′-tetrakis(methylthio)dithieno(3,4-b:3′,4′-d)thiophene 8 have been synthesised and their cyclovoltammetric behaviour together with their ability to form cation radical salts and charge transfer compounds have been studied.