To screen suitable ionic liquids (ILs) for the extraction separation of benzene and cyclohexane, a close-boiling mixture, measurement of the corresponding liquid-liquid equilibria (LLE) data is necessary. Toward this aim, LLE data for ternary systems of ILs + benzene + cyclohexane were measured at atmospheric pressure and (298.2 and 313.2) K, and the experimental data were correlated using the nonelectrolyte NRTL equation. The ILs used in this work are 1-methyl-3-methylimidazolium dimethylphosphate ([C(1)mim][DMP]) and I-ethyl-3-methylimidazolium diethylphosphate ([C(2)min][DEP]). It was found that the selectivity of [C(1)mim][DMP] and [C(2)mim][DEP] for benzene is in the range of (4.4 to 2.9) and (4.3 to 2.5), respectively, and the selectivity is virtually independent of temperature in the temperature and concentration range studied. Considering the high extraction capacity and selectivity for benzene as well negligible solubility in benzene + cyclohexane mixtures, [C(2)min][DEP] may be used as a potential extracting solvent for the separation of benzene and cyclohexane.