Diallyl phthalate was photopolymerized with (SHCH2CH2OCH2)(2) in two 1-R-3-methylimidazolium bis(trifluoromethylsulfonyl) imides (R = Bu or Et) to study the polymerization kinetics (content 30-90% by mass) in air at 25 degrees C by differential scanning calorimetry. The polymerization occured with higher rates, in shorter time and to higher conversions than that without the ionic liqs. The obsd. effect of ionic liqs. was associated both with intermol. interactions in the ternary system as well as with its viscosity.