Aqueous solubilities of xanthene (C(13)H(10)O), anthrone (C(14)H(10)O), xanthone (C(13)H(8)O(2)), thioxanthone (C(13)H(8)OS), 9,10-anthraquinone (C(14)H(8)O(2)), and 9,10-phenanthrenequinone (C(14)H(8)O(2)) were measured at temperatures from 313 K to the solute melting point and pressures close to 5 MPa by a dynamic method combined with gas chromatography/mass spectrometry. The experimental solubilities were used to estimate the activity coefficients of the solutes in the aqueous solutions at saturation. Relative rates of increase of solute solubility (mole fraction) with temperature ranged from 0.049 K(-1) to 0.056 K(-1).