The vapor-liquid equilibrium (VILE) and boiling point data have been measured at 95.3 kPa for the binary systems of dimethylsulfoxide (DMSO) with substituted benzenes, of different compositions, by Swietoslawski-ebulliometer. Substituted benzenes include toluene, ethylbenzene, chlorobenzene, bromobenzene and nitrobenzene. The experimental temperature-composition (T-x) data were used to estimate Wilson parameters and then used to calculate the equilibrium vapor compositions and the excess Gibbs free energy at 298.15 K. The experimental results are analyzed in terms of intermolecular interactions between component molecules. The excess Gibbs free energies are positive for the systems DMSO + ethylbenzene and bromobenzene, whereas negative G(E) values are observed for the systems DMSO + toluene, chlorobenzene and nitrobenzene. Moreover, several predictive empirical relations were applied to predict the VLE data. (c) 2007 Elsevier B.V. All rights reserved.