The solubilities of hexaquonickel(II) bis(p-toluenesulfonate) [Ni(OTs)(2)center dot 6H(2)O] in an ethanol water mixture containing a mole fraction of 0-0.342 ethanol were measured at temperatures ranging from 288.15 to 333.15 K by using a synthetic method. The experimental data were fitted using the van't Hoff plot, the modified Apelblat equation, the general single model, and the hybrid model. All of these models show good agreement with the experimental data. The solubility of Ni(OTs)(2)center dot 6H(2)O increases with an increase of the temperature and the initial mole fraction of ethanol in the mixed solvents. Further, the molecular modeling studies using Materials Studio DMol(3) (Accelrys Software Inc.) indicated that the solubility of Ni(OTs)(2)center dot 6H(2)O depends not only on the polarities of the solvents but also on the interactions between Ni(OTs)(2)center dot 6H(2)O and solvent molecules. The enthalpy, Gibbs energy, and entropy of the solution process were derived by the modified van't Hoff equation.