We report here pi-conjugated Small molecules and polymers based on the new pi-acceptor building block, bithiophenesulfonamide (BTSA). Molecular orbital computations and optical, electrochemical, and crystal structure analyses illuminate the architecture and electronic structure of the BTSA unit versus other acceptor building blocks. Field-effect transistors and photovoltaic cells demonstrate that BTSA is a promising unit for the construction of pi-conjugated semiconducting materials.