The solubilities of adipic acid in cyclohexanol + cyclohexanone mixtures from 303.0 to 353.0 K and in cyclohexanone + cyclohexane mixtures from 303.0 to 378.5 K were determined using a titration and an in situ ATR-FTIR method. The averaged relative deviation between two methods at given temperatures was less than 2%. The solubility of adipic acid in cyclohexanone + cyclohexane mixtures increases with increasing mass fraction of cyclohexanone in the mixtures at given temperatures. However, the solubility of adipic acid in cyclohexanol + cyclohexanone mixtures reaches the maximum at cyclohexanone mass fraction of 0.4. The experimental data were well correlated by Apelblat equation and λh equation. The thermodynamics functions of the dissolution process were calculated by van’t Hoff equation.