Densities rho and speeds of sound u, of binary mixtures formed by o-toluidine or m-toluidine with diisopropyl ether (DIPE) or oxolane have been measured over the entire range of composition at a temperature of (303.15, 313.15 and 323.15) K and atmospheric pressure. The rho and u values were used to calculate isentropic compressibilities kappa(S), Rao's molar sound functions R, intermolecular free lengths L-f, specific acoustic impedances Z. excess molar volumes V-m(E), excess isentropic compressibilities kappa(E)(S), excess intermolecular free lengths L-f(E) and excess specific acoustic impedances Z(E). The results have been used to investigate molecular interactions and structural effects in these mixtures. The speed of sound in present mixtures has been estimated using several empirical and theoretical models to determine their relative predicting ability in terms of pure component properties. (C) 2011 Elsevier B.V. All rights reserved.