Toward near-infrared chiroptically active photonics polymers, anew type of optically active polyacetylene bearing L-alanine and electrochromic viologen in the side chains was prepared and carefully studied for the chiroptical properties. The resulting polymer exhibited much larger optical rotation ([m](25)(D) = -1310 degrees, DMF) than the model compound ([phi]D-25 = 201 degrees, DMF) as well as a strong negative circular dichroism (CD) signal attributable to backbone absorption, indicating the formation of a single-handed helical structure of the polymer main chain. The content of viologen in the polymer was determined to be > 70 mol % relative to the repeat unit by NMR and X-ray photoelectron spectrscopy. Because of the chiral perturbation of the helical main chain, the viologens in the side chains are asymmetrically positioned and interacted to yield a new strong negative CD band at long wavelengths (i.e., 450-800 nm) upon reduction to radical cations. The intensity of this CD signal could be easily switched between nearly 0 and -1.0 x 10(4) deg cm(2) dmol(-1) by redox cycles, which Could be repeated for Five times without incurring any deterioration of the sample solution. The rotatory strength of the CD signal was calculated to be 1.3 x 10(-40) esu(2) cm(2) according to Moffitt and Moscowitz's equation, which should coil tribute non trivially to the chit-optical properties of the polymer at the near-infrared spectral region.