The effect of cross-linking density (C-x) on volume phase transition of two liquid crystalline (LC) networks comprising dissimilar mesogens in a low molar mass LC has been investigated. Cross-linking density alters the modulus and nematicity of LC network each of which directly influence one of the three governing forces (elastic force, nematic interaction, isotropic mixing interaction) for the equilibrium swelling: An increment in C-x increases the network modulus, while it reduces the nematic-isotropic transition temperature of the pure (dry) LC network (T-NI(N)). The LC networks in the nematogen are discontinuously transformed from the swollen state into the shrunken state, as a result of a single nematic phase formation inside the gel at T-NI(G). It has been found that as C-x increases, the magnitude of discontinuous volume change at T-NI(G) decreases; T-NI(G) shifts to higher temperatures, which is opposite to the C-x dependence of T-NI(N). As an extreme case of high cross-linking density, the LC networks with C-x = 10 mol % in the nematic solvent exhibits the nematic-isotropic transition but do not undergo appreciable volume transition. The experimental swelling-temperature curves are compared with the prediction of a mean field theory for nematic gel. The theory successfully describes the effect of cross-linking density on the swelling and phase behavior observed. (C) 2003 American Institute of Physics.