Solubilities of diethyl phthalate (DEP), dicyclopentadiene (DCPD), and styrene in ionic liquid 1-ethyl-3-methylimidazolium acetate ([Emim][OAc]) were measured in the temperature range T = (283.15-353.15) K and at atmospheric pressure (101.3 kPa) the corresponding temperature-composition phase diagrams were obtained. Solubilities of DEP and DCPD in [Emim][OAc] increase with temperature but the solubility of styrene in [Emim] [OAc] decreases with temperature. The ternary liquid-liquid equilibrium data for the system of styrene + glycerol + [Emim][OAc] were also determined at temperatures of 298.15, 308.15, 318.15, and 328.15 K, and the results indicate that the addition of glycerol can significantly reduce the solubility of styrene in [Emim] [OAc]. For the ternary system, when the amount of glycerol is enough, the solubility of styrene in [Emirri][OAc] increases with temperature. The experimental data were correlated by the nonrandom two-liquid activity coefficient model and the binary interaction parameters were obtained.