In this study, experimental vapor liquid equilibrium (VLE) behavior for two quaternary carbon dioxide + ethanol + thiophene + (pentane or nonane) systems was measured by means of a static analytic apparatus with online sampling. The VLE data was obtained at (similar to 334.2 and similar to 363.8) K. Carbon dioxide + ethanol was used as a solvent + cosolvent mixture prepared in a solute-free basis of 0.033 mass fraction ethanol. The solute mixture, constituted by the sulfur compound + linear alkane, was used to determine the feasibility to extract the sulfur compound in the studied range. Standard uncertainties Cu) for the measured properties are estimated to be p +/- 0.02 MPa, T +/- 0.04 K, and x(1) +/- 0.0028, y(1) +/- 0.0015 mole fraction for these last two values. According to the results, the vapor phase is enriched with pentane compared with the sulfur compound. On the other hand, high separation factors for thiophene over nonane are obtained at low pressures.