Excess molar volumes. V(E), excess molar enthalpies, H(E), speeds of sound, u, and vapor-liquid equilibrium data of tetrahydropyran (1) + aniline or N-methylaniline or 2-methylaniline (2) binary mixtures have been measured over the entire mole fraction range at 308.15 K. Speeds of sound and vapor-liquid equilibrium data have been utilized to predict isentropic compressibility changes of mixing, K(S)(E), and excess Gibbs free energy, G(E). The observed V(E), H(E), K(S)(E), and G(E) data have been analyzed in ten its of Graph theory. It has been observed that V(E), H(E), K(S)(E). and G(E) predicted by Graph theory compare well with their corresponding experimental values.