The solid-liquid equilibrium phase diagram of Nicotinamide (NA)- 2-Methylimidazole(MIM) system in form of temperature-composition curve determined by Thaw- melt method, suggests the formation of simple eutectic(E) at 102°C and at 0.451 mole fraction of MIM. The excess thermodynamic quantities have been determined by computing heat of fusion data and activity coefficient of the component in binary mix. These values highlight the ordering, stability and structure of eutectic and non-eutectic alloys. The thermodynamic mixing functions describe about the nature of mixing of the components during alloying. The Gibb's-Duhem equations give the graphical solution of activity, activity coefficient and partial mixing thermodynamic quantities.