The mutual solubilities of [EMIM][EtSO4], namely, I-ethyl-3-methylimidazolium ethylsulfate, with n-alkanes (hexane or octane), aromatic hydrocarbons (benzene, toluene, or ethylbenzene), ketones (pentan-2-one, pentan-3-one, hexan-2-one, or heptan-4-one), ethers (dibutyl ether, tert-butyl-methyl ether, tert-butyl-ethyl ether, or tetrahydrofuran), and with dimethylsulfoxide, DMSO, have been measured at ambient pressure by a dynamic method from (250 to 420) K. The upper critical solution temperatures (UCSTs) were not observed for these systems, because they were at a temperature > 420 K. The solubilities of [EMIM] [EtSO4] in n-alkanes and aromatic hydrocarbons decrease with an increase of the molecular weight of the solvent. The experimental results have been correlated using the NRTL equation. The average root-mean square deviation of the equilibrium mole fraction for all the liquid-liquid equilibrium (LLE) data was 0.0033.