Equilibrium solubilities of the two pesticides xanthone and xanthene in supercritical CO2 have been measured by using a dynamic flow method combined with gravimetric analysis. Determinations were carried out at 308.15 and 328.15 K for pressures ranging from 80 to 300 bar. The results show that xanthene is much more soluble in supercritical carbon dioxide than xanthone with its solubility over 10 times higher than that of xanthone, due to its higher volatility. The determined solubility data are well described by the Peng-Robinson equation of state and the empirical density based Chrastil model over the pressure and temperature ranges studied. (c) 2005 Published by Elsevier B.V.