The excess molar enthalpies of alkanediamine H2N-(CH2)(u-)-NH2 (u = 2, 3, 4) + benzene or toluene mixtures were measured using a Calvet microcalorimeter at 303.15 K. Group contribution models, Modified UNIFAC (Lyngby and Dortmund versions) and DISQUAC have been applied. The effects of the proximity of two NH2 groups in these mixtures is analysed.