Dithieno[2,3-d;2′,3′-d]benzo[2,1-b;3,4-b′]dithiophene: a novel building-block for a planar copolymer

A planar heteroacene building block, dithieno[2,3-d;2',3'-d']benzo[1,2-b;3,4-b']dithiophene (DTmBDT), is reported via a facile synthetic procedure. Single-crystal X-ray diffraction of Br-2-DTmBDT reveals that dodecyl chains interdigitate, still enabling close pi-stacking of 3.42 angstrom. A very high molecular weight quasi-planar copolymer PDTmBDT-DPP exhibited a high hole mobility of 0.36 cm(2) V-1 s(-1) in preliminary studies of organic field-effect transistors.