The ternary system composed of phenol, m-cresol and supercritical carbon dioxide is characterized by unusual phase behaviour. In fact the ternary diagram shows five distinct regions : a three phase region of solid-liquid-gas, two two phase regions liquid-solid and liquid-gas, and two single phase regions liquid and gas. In addition when pressure was increased and temperatures were below the temperature of fusion of phenol, it was observed that the carbon dioxide causes recrystallization of phenol from the liquid phase. To understand and to describe all these phenomena, several experimental measurements were performed and are reported in this paper. Finally, using all the available data for the pure compounds as well as for the three binary sub-systems, a modified Peng-Robinson Equation of State was parametrized and then used to describe, at least qualitatively, the multicomponent multiphase behaviour in the whole range of composition under different values of pressure and temperature.