A conjugated ionic polymer with long alkyl substituents was prepared by the uncatalyzed polymerization of 2-ethynylpyridine. The polymerization of 2-ethynylpyridine by using 1-bromooctadecane proceed well in homogeneous manner to give a high yield (87%) of polymer. The polymer structure was characterized by various instrumental methods to have conjugated polymer backbone with the designed substituents. The electro-optical and electrochemical properties of the resulting poly(2-ethynyl-N-octadecylpyridinium bromide) were measured and discussed. The photoluminescence spectrum of polymer showed that the peak is located at 596 nm corresponding to the photon energy of 2.08 eV. This polymer showed the well-defined and stable redox process. (C) 2013 Elsevier B.V. All rights reserved.