Based on experimental data a kinetic model is presented that adequately describes the main features of preferential solvation of a charge-transfer dipole in binary mixtures. 8-(N,N-dimethylamino)-11H-indeno[2,1-a]pyrene is used as fluorescent probe in toluene/DMSO mixtures. The observed saturation behavior can be understood in terms of microclusters of polar molecules surrounding the solute dipolar species. In such an approach, the size of the microclusters is mainly determined by interfacial surface tension.