The equilibrated grain boundary groove shapes for Succinonitrile (SCN) solid solution in equilibrium with the Succinonitrile (SCN)-D Camphor (DC) eutectic liquid were directly observed. From the observed grain boundary groove shapes, the Gibbs-Thomson coefficient and solid-liquid interface energy for SCN solid solution in equilibrium with the SCN-DC eutectic liquid has been determined to be (5.39 +/- 0.27) x 10(-8) K m and (7.88 +/- 0.79) x 10(-3) J m(-2) with present numerical method and Gibbs-Thomson equation, respectively. The grain boundary energy of SCN rich phase of the SCN-DC eutectic system has been determined to be (14.95 +/- 1.79) x 10(-3) J m(-2) from the observed grain boundary groove shapes. Thermal conductivity ratio of the liquid phase to the solid phase for SCN-0.16 mole % DC alloy has also been measured.