By irradiating evaporated 10,12-pentacosadiynoic acid (p-DA) monomer film with circularly polarized light (CPL), we prepared chiral poly (diacetylene)[PDA] film. The circular dichroism (CD) was obtained reproducibly, depending on the rotational direction of the CPL The induced chirality showed the dependence on the substrate temperature used for the preparation of evaporated p-DA monomer films, and it was stable after the transition to red-phase by annealing. Results suggest that side chain of polymer made a significant contribution to the formation of red-phase chiral PDA. (C) 2009 Elsevier B.V. All rights reserved.