For THF solutions of an optically active helical poly[3,5-bis(hydroxymethyl)phenylacetylene] derivative bearing a biphenyl group, photoexcitation of the terphenyl moiety at 300 nm led to photoluminescence at 390 nm. On the other hand, the photoluminescence resulting from excitation at 280 nm caused dual emission at 310 and 390 nm, whose intensities were tuned by the polar-solvent stimuli which induced the collapse of the intramolecular stack structure of the side groups, and the change in the emission wavelength accompanied disappearance of the optical activity.