Provided is a process for producing polypyridinium having a narrow molecular weight distribution and a desired molecular weight. A pyridine derivative monomer (2) is polymerized with a polymerization initiator (1) specially designed, such as a 4-halopyridinium, in the presence of a dissolution accelerator (e.g., tetrabutylammonium tetrafluoroborate) for dissolving the polymer to be yielded in a solvent to thereby synthesize a polypyridinium (3) having a narrow molecular weight distribution and a desired molecular weight, as shown in the following scheme. (In the scheme, Y is an anion dissolving in the organic solvent; X and Z each is halogeno; R is a hydrocarbon group, etc.; and o is 1 to about 300). |