Several kinds of symmetric and asymmetric phenylene-thienylene co-oligomers substituted with alkyl, alkoxy, ester or cyano groups in the ends were newly synthesized. Liquid-crystalline (LC) properties of these compounds were evaluated by differential scanning calorimetry and polarizing optical microscopy. It was found that all the compounds showed an LC phase. The photoinduced reorientation behavior of the dye-doped nematic LCs was investigated upon exposure to an Ar+ laser beam at 488 nm. The change in refractive index was estimated to be larger than 0.1. It was revealed that the dyes synthesized act as an efficient trigger for the photoinduced reorientation.