Solid-liquid equilibria in a wide range of concentrations for binary mixtures of epsilon-caprolactam (CL) and cyclohexanone oxime (CHO) with 1-butyl-3-methylimidazolium hexafluorophosphate ([C(4)MIM][PF(6)]), 1-butyl-3-methylimidazoium tetrafluoroborate ([C(4)MIM][BF(4)]), and 1-methyl-3-tetradecylimidazolium bis-(trifluoromethanesulfonyl)imide ([C(14)MIM][NTf(2)]) and CHO with 1-butyl-3-methylimidazolium tosylate ([C(4)MIM][Tos]) have been studied in this work. Activity coefficients of the components in the saturated solutions were evaluated. Solution enthalpies of the solutes were determined. Solubilities and activity coefficients of CL and CHO in their solutions with 1,3-dialkylimidazolium ionic liquids were compared.