Bis[1,3]thiazolo[4,5-f:5',4'-h]thieno[3,4-b]quinoxaline Derivatives as New Building Blocks of Polymers for Organic Electronics

New derivatives of bis[1,3]thiazolo[4,5-f:5',4'-h]thieno[3,4-b]quinoxaline containing the fused thiadiazoloquinoxaline moiety have been prepared. Monomer M1 shows strong light absorption within 600–800 nm due to intramolecular charge transfer. The optical bandgap E g opt determined from the absorption edge in a film is 1.44 eV. The HOMO and LUMO levels are–5.44 and–3.12 eV, respectively. The new structural fragment has a rather low frontier molecular orbital energies and a small bandgap; therefore, it is a promising building block for the synthesis of polymers for organic electronics.