Abstract2‐Vinylpyridine can polymerize spontaneously by adding small amounts of methyliodide. The polymer obtained at low conversion has a quaternization degree of ∼80%. We concluded this polymerization to be charge‐transfer copolymerization of radical nature between 2‐vinylpyridine and its quaternized derivative, N‐methyl‐2‐vinylpyridinium iodide. The intramolecular charge‐transfer interaction between monomer units in the polymer molecule was observed by means of the spectrophotometric measurement, suggesting similar interaction b