Excess molar enthalpies and excess molar volumes at T = 298.15 K and p = 0.101325 MPa are reported for (N-methyl-2-pyrrolidinone + benzene, or methyl benzene, or 1,2-dimethyl benzene, or 1,3-dimethyl benzene, or 1,4-dimethyl benzene, or 1,3,5-trimethyl benzene, or ethyl benzene). The excess enthalpy ranges from a minimum of -546 J . mol(-1) for benzene to a maximum of 336 J . mol(-1) for 1,3,5-trimethyl benzene. The excess molar volumes are negative for all the mixtures. The Redlich-Kister equation was fitted to the data, and the ERAS model was used to correlate the data. The experimental results were interpreted in terms of associative and dissociative effects.