The theory of Brochard et al. for mixtures of nematogens is applied to the case of crosslinked polymers with side chain liquid crystals and low- molecular-weight liquid crystals. Phase equilibria of those mixtures are analyzed by allowing the Flory-Huggins interaction parameter for isotropic mixture and the rubber elasticity parameters of the elastic network, to be functions of the polymer volume fraction. A wide range of crosslinking density is covered showing a strong influence on the phase behavior of such compounds. The clearing temperature of nematic-isotropic transition of each nematogen is different and the cross-nematic interaction parameter is a geometric average of the parameters for pure nematogens.