The synthesis and characterization of a new family of soluble oligothiophene-S,S-dioxides and their use as building blocks to form polythiophene-S,S-dioxides via microwave-assisted Stille coupling polymerization are described. Incorporation of the sulfone group into the polythiophene backbone leads to narrowing of the polymer bandgap, and while the energies of both Frontier orbitals in polythiophene-S,S-dioxide are lower with respect to polythiophenes, this tendency is considerably stronger for the lowest unoccupied molecular orbital than for the highest occupied molecular orbital, resulting in greater electron-accepting ability. (C) 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 49: 1933-1941, 2011