Stereoregular cis-transoidal poly(phenylacetylene) bearing a phosphonic acid monoethyl ester as the pendant group (poly-1-H) was found to form a preferred-handed helix upon complexation with various optically active pyrrolidines and piperazines in dilute dimethyl sulfoxide and water, and the complexes exhibited characteristic induced circular dichroisms (ICDs) in the UV-vis region of the polymer backbone. The Cotton effect signs in water reflect the absolute configuration of the pyrrolidines. The sodium salt of poly-1-H (poly-1-Na) and poly-1-H in the presence of optically active amines formed lyotropic nematic and cholesteric liquid crystalline phases in concentrated water solutions, respectively, indicating the rigid-rod characteristic of the polymer main chain regardless of the lack of a single-handed helix, as evidenced by the long persistence length of about 18 nm before and after the preferred-handed helicity induction in the polymer. X-ray diffraction of the oriented films of the nematic and cholesteric liquid crystalline polymers exhibited almost the same diffraction pattern, suggesting that both polymers have the same helical structure; dynamically racemic and one-handed helices, respectively. On the basis of the X-ray analysis, a possible helical structure of poly-1 is proposed. (C) 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 1383-1390, 2010