Disclosed are novel poly(benzodithiophenes), their use as semiconductors or charge transport materials in optical, electro-optical or electronic devices, for example, liquid crystal displays, optical films, organic field effect transistors (FET or OFET) for thin film transistor liquid crystal displays and integrated circuit devices such as RFID tags, electroluminescent devices in flat panel displays, and in photovoltaic and sensor devices, and to a field effect transistor, light emitting device or ID tag.