The copolymerization behavior of mixtures of an acidic and a basic monomer were studied as a function of the monomer feed composition. The four systems investigated in this way comprised APSA/1‐VIm, APSA/4‐VP, APSA/DAMA, and SSA/1‐VIm. The corresponding polyelectrolytes were obtained by free radical polymerization of the monomer mixtures in solution, while the isolated monomeric salts of equivalent amounts of both monomers were prone to spontaneous polymerization. For APSA/1‐VIm, APSA/4‐VP, and APSA/DAMA, a donor‐acceptor relationship was found, whereas for SSA/1‐VIm the SSA was favorably incorporated over all feed ratios. High Tg and complex viscosity data indicated a considerable degree of ionic, thermally reversible crosslinking within the polymers that were thermally stable up to at least 230 °C.magnified image