3,4-Dithia-7H-cyclopenta[a]pentalene

4H-cyclopenta[2,1-b:3,4-b′]dithiophene, also known as CPDT, a rigid coplanar structure favouring π?π intermolecular interactions with good electron-donating properties, has been one of the most attractive building blocks for organic field effect transistors and organic electronics. The five-member ring in the middle also offer the function to have side-chain manipulation to enhance solubility in solutions for device fabrications, morphology and polymer processing. One of the intensively studied polymer for organic electrons, PCPDTBT, with the alternating CPDT and 2,1,3- benzothiadiazole (BT) units, has demonstrated device performance of PCE over 6% [5]

4H-Cyclopenta[2,1-b:3,4-b'']dithiophene is useful in the synthesis of donor-acceptor copolymers.