Donor−Acceptor-Substituted Phenylethenyl Bithiophenes:  Highly Efficient and Stable Nonlinear Optical Chromophores

For practical applications of poled electrooptic polymers, highly efficient and thermally stable nonlinear optical (NLO) chromophores are required. We describe here a concise synthesis and characterization of a series of donor−acceptor chromophores incorporating a bithiophene moiety in the conjugated bridge. They display a suitable thermal stability and significantly enhanced molecular nonlinearity as compared to their monothiophene analogues and are among the most efficient yet stable NLO chromophores prepared so far.