The hitherto rarely used multicomponent Radziszewski reaction was applied to synthesize imidazolium-containing polymers under mild conditions with industrial feasible monomers. The polymerization process proved to be very efficient, yielding highly pure water-soluble polyimidazolium salts (PIMs) in one step. Reaction parameters were studied, and concentration and molar ratio of the starting materials were identified as important parameters for molecular weight control. Surprisingly, it was found that nonstiochiometrical ratios of the starting materials can be used to obtain high molecular weight PIMs. Polymerization using different amine monomers demonstrated the broad scope of the poly-Radziszewski reaction. PIMs containing hydrophilic, hydrophobic, or even zwitterionic moieties were accessible-via the simple one-step procedure.