The sorption properties of CO2 in several side-chain liquid crystalline polymers (side-chain LCPs) with various mesophases have been investigated. The equilibrium concentrations of the sorbed CO2 were measured over a wide temperature range, covering the whole of the phase states of the side-chain LCPs. The concentrations have been found to depend strongly on the phase state of the polymers. They increase significantly at the various phase transitions, i.e. crystalline to smectic, smectic to nematic, and liquid crystalline (smectic or nematic) to isotropic. A correlation between the solubility changes and the enthalpies of the transitions has been established.