Isoplethic phase diagrams were measured for the system 4'-pentyloxy-4-cyanobiphenyl + CO2 for CO2 mole fractions up to 0.72, in temperature range 280-360 K and at pressures up to 12 MPa using a synthetic method with visual observation. It is found that pure 4'-pentyloxy-4-cyanobiphenyl shows two different solid phases, a nematic liquid phase (N) and an isotropic liquid phase (I-2). For the binary system, liquid-liquid demixing (I-1 + I-2) was found. The following phase equilibria were measured: I-2 + gas <-> I-2, N + gas <-> N, solid + N <-> N, solid + I-2 <-> I-2, N <-> N + I-2 and N + I-2 <-> I-2. Further, points of the three-phase curves (solid + N + gas), (N + I-2 + gas), (solid + N + I-2), (solid + I-1 + I-2) and (I-1 + I-2 + gas) were determined experimentally. Based on these measurements a P, T-projection of the system was constructed. At 341 K, the molar Henry coefficient of the isotropic phase was determined to be 13.7 MPa. (C) 2012 Elsevier Ltd. All rights reserved.