The isobaric vapor-liquid equilibrium (VLE) data were determined, by using a recirculation type apparatus, for the binary mixtures of nonane with cyclohexane, toluene, m-xylene, or p-xylene at 101.3 kPa. All the data passed the thermodynamic consistency test and no azeotrope was formed in the investigated binary systems. While nonane + p-xylene were found to behave as near ideal systems, nonane+ cyclohexane, nonane + toluene, and nonane + m-xylene exhibited large deviations from ideal behavior. The experimental results were used as a basis to check the validity of two predictive models, the UNIFAC and the conductor-like screening model for realistic solvents (COSMO-RS) models. These new VLE data were also correlated with the Wilson, the NRTL, and the UNIQUAC activity coefficient models. (C) 2011 Elsevier B.V. All rights reserved.