The phase equilibrium of an organic analogue of a nonmetal-nonmetal system, involving resorcinol (R)-1,4-diiodobenzene (DIB), was established which shows solid is in equilibrium with liquid as well as two immiscible liquid phases are also in equilibrium with a liquid of single phase. The phase diagram study infers the formation of a monotectic and a eutectic at 0.05 and 0.97 mole fractions of resorcinol, respectively. Using X-ray diffraction technique, the range of solid solubility of R in DIB and DIB in R was studied. The thermal properties of materials such as heat of mixing, entropy of fusion, roughness parameter, interfacial energy and excess thermodynamic functions were computed from the enthalpy of fusion values, determined using differential scanning calorimeter (DSC) method. The solid-liquid interfacial energy shows the applicability of non-wetting condition. The effect of solid-liquid interfacial energy on morphological change of monotectic growth has also been discussed. The microstructures of monotectic, eutectic and pure components were taken and have shown their peculiar characteristic features. (C) 2009 Elsevier B.V. All rights reserved