Six imidazolium ionic ligs. and a non-ionic tricresyl phosphate were used as diluents (50-70% by mass) for photopolymerization of poly(ethylene glycol) monomethacrylate to det. the reaction kinetics. An increase in the polymerization rate in the ionic ligs. was achieved despite a significant dun, of the monomer. In the nonionic diluent, only a redn. of the gel effect was obsd. Structure of the anions showed a stronger effect on the polymerization rate than the length of the imidazole ring substituents. The obsd. differences resulted from a different influence of the particular ionic ligs. on the increase of the propagation rate coeft. and decrease of the termination rate coeft.