Binary phase diagrams of several polynuclear aromatic hydrocarbons in wash oil including dibenzofuran + anthracene, dibenzofuran + carbazole, acenaphthene + carbazole, acenaphthene + anthracene, fluorene + anthracene, and fluorene + carbazole have been determined using differential scanning calorimetry (DSC). The results show that the former five systems are simple eutectic systems. The Ott equation and regular solution equation were employed to correlate the solid-liquid equilibrium data. Both two equations can accurately represent the nonideality of the liquid-phase for the former five systems. As to system of fluorene + carbazole, it turns out to form solid solution at any composition. Further, the experimental data were correlated using regular solution equation. The correlated results are also in good agreement with the experimental data. (C) 2012 Elsevier B.V. All rights reserved.