Methods for the estimation of the differential molar heat capacity, the difference between the heat capacity of the solid and the liquid form of organic compounds at their melting point &UDelta; c(p)-(T-m), are presented. Three schemes are considered: the first involves use of group contribution methods for the prediction of solid heat capacity (c(p)(S)) and liquid heat capacity (c(p)(L)); the other two, empirical correlations through the entropy of fusion at the melting point &UDelta; S-f(T-m). Recommendations for the different categories of organic compounds are made that provide substantial improvement over the commonly used assumption of &UDelta; c(p) = 0, in the prediction of ideal solid solubility and solid vapor pressure.