Synthesis and function of helical polyphenylacetylenes are briefly reviewed. Optically active helical polyphenylacetylenes were synthesized by polymerization of the corresponding chiral phenylacetylene monomers and their chiral recognition abilities were evaluated as a chiral stationary phase for HPLC. The polyphenylacetylenes showed high chiral recognition and could resolve some racemic compounds. Conceptually new helical polyphenylacetylenes were found to be induced on optically inactive polyphenylacetylenes bearing functional groups upon complexation with optically active small molecules capable of interacting with the polymers. The complexes exhibited a characteristic induced circular dichroism in the UV-visible region in organic solvents as well as in water, which could be used to determine the absolute configuration of chiral molecules. A unique helical polyacetylene bearing a β-cyclodextrin as the side group that exhibits the inversion of macromolecular helicity accompanied with a color change is also described.