A new polyacetylene polyelectrolyte with 2-ethynyl-N-nonanoylpyridinium chloride as substituent was easily synthesized via the catalyst-free polymerization of 2-ethynylpyridine by nonanoyl chloride. The polymerization of produced monomeric salt, 2-ethynyl-N-nonanoylpyridinium chloride, firstly formed by the quaternization of 2-ethynylpyridine using nonanoyl chloride, proceeded well to give the corresponding polyacetylene derivative in high yield (89 %). Various instrumental analysis results on polymer structure revealed that the polymer have the polyacetylene backbone system with the designed substituents. This polymer was completely soluble in such organic solvent as methanol, DMF, DMAc, DMSO, NMP etc. This polymer exhibited more hygroscopic property because of its ionic character. The optical and electrochemical properties of polymer were measured and discussed. This polymer showed the irreversible electrochemical behaviors between the oxidation and reduction peaks. It also showed stable redox system up to 50 cycles as similiar with those of other ionic polyacetylene derivatives.