In this paper, a new approach to model cocrystal phase diagrams is presented. Starting from an initial set of data, the phase diagram is obtained from discontinuous isoperibolic thermal analysis (DITA) and basic thermodynamic data (enthalpies and solubilities). The solubility product constant may then be determined. Since this constant is solvent independent, extrapolation to other solvents is possible. Application of this technique to an active pharmaceutical ingredient and glutaric acid demonstrates good agreement between calculated and experimental data.