The molecular interactions between asphaltenes and solvents are an important parameter that dominates the processing behavior of asphaltenes. This study has developed a method for estimating the interaction energy of asphaltene (or resin) aggregates with aromatic solvent molecules. The thermal properties of three asphaltenes and one resin have been ascertained using differential scanning calorimetry (DSC) and thermogravimetry analysis (TGA), and the heats of solution (Delta H-solu) of the two species in quinoline, 1-methyl naphthalene (1-MN), and tetralin have been established using microcalorimetry. By combining the two techniques, the heat of mixing (Delta H-mix) of the asphaltene or the resin with the solvents could be estimated. This not only evaluates the nature of interactions between asphaltene (or resin) aggregates and solvent but also provides a quantitative estimate of their magnitude.