Some thermodynamic quantities were obtained for the interactions of poly [2-(3-phenyl -3- methylcyclobutyl)-2-hydroxyethyl methacrylate-co-methacrylic acid] Poly (PCHEMA-co-MA) with alcohols, ketones, acetates, aromatics and n-alkanes by inverse gas chromatography in the temperature range of 150-180oC. The specific retention volumes, Vgo, weight fraction activity coefficients of solute probes at infinite dilution, $Omega 1infty$ and Flory-Huggins thermodynamic interaction parameters, $chi 12infty$ between polymers and solvents were determined. The partial molar free energy, $Delta G1infty$ , the partial molar heat of mixing, $Delta H1infty$ , at infinite dilution and the solubility parameters of the polymer, $delta$2 , were calculated. The copolymer was characterized by 1 H-NMR, FT-IR and DSC analyses