Densities rho, dynamic viscosities eta, for binary mixtures of toluene with some n-alkanes, namely, n-pentane, n-hexane, n-heptane, n-octane, n-nonane, and n-decane have been measured over the complete composition range. Excess molar volumes V-E, viscosity deviations Delta(eta), and excess Gibbs free energy of activation Delta G(*E), were calculated there from and were correlated by Redlich Kister type function in terms of mole fractions. For mixtures of toluene with n-pentane and n-hexane the VE is negative and for the remaining systems is positive. The Delta eta values are negative for all the studied mixtures. The Delta G(*E) values shows the positive values for the binary mixtures with n-decane, whereas the negative values have been observed for all the remaining binary mixtures. From the results, the excess thermal expansivities at constant pressure alpha(E), is also estimated. The Prigogine-Flory-Patterson (PFP) theory and its applicability in predicting V-E is tested. The results obtained for viscosity of binary mixtures were used to test the semi-empirical relations of Grunberg and Nissan, Tamura and Kurata, Hind et al., Katti and Chaudhri, McAllister, Heric, Kendall, and Monroe. The experimental on the constituted binaries are analyzed to discus the nature and strength of intermolecular interactions in these mixtures. (c) 2005 Elsevier Ltd. All rights reserved.