A substituted polypyrrole (PPr) with viologen side groups (polymer-1) was obtained from the reaction of N-aminopyrrole with 1-hexyl-1'-(2,4-dinitrophenyl)-4,4'-bipyridinium dihalide (salt-1). A model compound (model-1) was synthesized by the reaction of N-aminopyrrole with N-(2,4-dinitrophenyl)-4-(4-pyridyl)pyridinium chloride (salt-2). UV-vis spectra revealed that polymer-1 had an expanded pi-conjugation system along the polymer chain: the polymer showed an onset position of absorption at a wavelength approximately 200 nm longer than the corresponding wavelength of model-1. Polymer-1 received an electrochemical oxidation of the pyrrole ring and reduction of the viologen group within the polymer.