A new ionic polyacetylene was synthesized via the non-catalyst polymerization of 2-ethynylpyridine using phosphorus oxychloride. The polymerization proceeded well in homogeneous manner to give a moderate yield of polymer (74%). The resulting polymer was completely soluble in polar organic solvents including water. The photoluminescence spectrum showed the two maximum peaks of 471nm and 489nm corresponding to the photon energy of 2.64eV and 2.54eV, respectively. The oxidation and reduction onset potentials of polymer were observed at 970 and -130mV, respectively.