This paper deals with the thermodynamic aspects of solvatochromic and halochromic systems. Enthalpic measurements of dilution of solutions of the E-T(30) dye in various alcohols and in the presence of increasing concentrations of sodium iodide were carried out by means of calorimetric techniques. Contrary to observations based on purely spectroscopic methods, these calorimetric measurements showed evidences of dye aggregation in solution. In addition, the results confirmed the existence of previously described dye-cation associations in the organic media.