Propiolic esters having various chiral substituents, [HCtCCO2R*, R* ) (S)-(CH2)nCHMeEt (n ) 0-5), (1S,2R,5R)-isomenthyl, and (1S,2S,5S)-myrtanyl], were polymerized with [(nbd)RhCl]2 or MoOCl4-n-Bu4Sn for the purposes of establishing the relationship between the helical conformations of the polymers and the structures of pendant chiral groups. In contrast to the poor stereoregularities of the polymers prepared with MoOCl4-n-Bu4Sn, [(nbd)RhCl]2-catalyzed polymerizations resulted in polymers with high cis contents. These stereoregular polymers with 1-4 alkylene spacers displayed intense CD effects and large optical rotations as well as large band gap energy (ca. 3.2 eV), indicating that they possess restricted main-chain conjugation and exist in helical conformations with an excess of a onehanded screw sense. In contrast, the polymers without alkylene spacers possessed more extended coplanarity of the main chains and exhibited poorer chiroptical properties than those bearing alkylene spacers. The introduction of bulkier substituents to the polymers enhanced the persistence length of the one-handed helix, resulting in an increase in the magnitude of Cotton effects and optical rotations. Polymer stereoregularity remarkably influenced the polymer conformation, and no distinct CD signals were detected for polymers with alkylene spacers if polymerizations were performed with the Mo catalyst.