BBT-2C6ThBr, namely 4,8-bis(5-bromo-4-hexylthiophene)-benzo[1,2-c;4,5-c']bis[1,2,5] thiadiazole, has been used as a building block for the synthesis of extremely low-band-gap OFET polymers such as PBBTSD and PBBTPD which extend the absorption to 1200 nm with onset at 2030 nm.
