On the basis of optimized structures of two kinds thiophene oligomers, we investigated the configuration and conformation dependent optical and electronic properties of α or β substituted oligothiophene (PT) and oligo(thienylenevinylene) (PTV) isomers, respectively, at the TD‐DFT/6‐31+G(d,p)//PBE0/6‐31G(d) level. The corresponding properties of polymers were predicted by extrapolation method. The broad absorption regions for polythiophene and/or poly(thienylenevinylene) can be ascribed to the coexistence of various conformational and/or configurational isomers with similar energies and each corresponding excited state possessing different absorption spectrum and overlapping each other. Furthermore, the reorganization energies for electron (λe) and hole (λh) of α or β substituted PTV and PT indicate them to be potential ambipolar charge transport materials under the proper operating conditions. Therefore, these results are important because they can provide a rational way for the design of multifunctional materials with broad absorption and ambipolar charge transport properties for solar cells devices. © 2010 Wiley Periodicals, Inc. Int J Quantum Chem, 2011