Optically active poly(diphenylacetylene) derivatives, poly(4-((S)-2-methoxyoctyloxy)diphenylacetylene)(poly-1), poly(4-((S)-2-triethylsiloxyoctyloxy)diphenylacetylene) (poly-2), and poly(4-(.(S)-2-hydoxyoctyloxy)diphenylacetylene) (poly-3), were successfully synthesized and were examined about their chiroptical and liquid crystalline properties. The mirror image of circular dichroic (CD) spectra of poly-1 and poly-2 in dilute Solution indicated that their polymer backbones adopted a helical conformation with the opposite handedness. Poly-3 prepared from poly-2 by deprotection of a triethylsilyl group showed the same helical handedness with poly-2. Poly-1-poly-3 had a lyotropic liquid crystalline property while thermotropic liquid crystalline behavior was observed for poly-1 and poly-3. Poly-1-poly-3 spin-cast films showed a strong bisignate CD signal centered at absorption band of polymer backbone, which suggested the formation of a chiral organization. Thermal annealing enhanced the induced chirality in poly-3 film and inversed the induced chirality in poly-1 film. Simple exposure to organic solvent vapor also enhanced the induced chirality in poly-1-poly-3 films. Furthermore, the intensity of induced chirality in poly-3 Film was reversibly controlled by exposing to appropriate solvent vapor alternately.