The solvents have considerable influence on chemical and physical processes (reaction rates, selectivity, chemical equilibria, position and intensity of spectral absorption bands).1 Solvent effects are closely related to the nature and extent of solute- solvent interactions locally developed in the immediate vicinity of the solutes. Solute- solvent interactions are much more complex in mixed solvents than in pure solvents due to the possibility of preferential solvation by any of the solvents present in the mixtures. Moreover, the solvent-solvent interactions produced in solvent mixtures can affect the solute-solvent interactions and therefore they can also affect preferential solvations.2-5