Phase diagram of o-nitroaniline-alpha-naphthol system has been investigated by thaw melt method and results showed the formation of a simple eutectic mixture. The values of the heat of fusion of components and eutectic mixture were determined with the help of DSC technique. Excess Gibb's free energy (G(E)), excess entropy (S-E) and excess enthalpy (H-E) of mixing were calculated. In order to know the nature of interaction between the two components, FT-IR spectral studies were made. The modulus of rupture of the pure components and the eutectic mixture were determined. The isotropic as well as the anisotropic solidification behavior were studied. Microstructural studies of o-nitroaniline showed the formation of lamellar with leafy like and alpha-naphthol showed the formation of broken rock like microstructures, whereas in the eutectic mixture, growth of flat crystals in different directions from a particular point were seen. Undercooling measurements were made. Optimized geometrical parameters, molecular properties and potential energy of the interacting molecules of the eutectic mixture have been examined using various computational methods. (C) 2014 Elsevier B.V. All rights reserved.