Cross-linkable gemini room temperature ionic liquids (GRTILs) were synthesized and photo-cross-linked into thin films. The resultant polymer membranes were tested for their permeabilitieS to CO2, N-2, CH4 and H-2. Permeabilities for each gas were found to be much lower when compared to previously reported poly(RTIL) membranes, mainly as a result of highly restricted diffusion. Separation factors were similar to previously studied poly(RTIL) membranes. CH4 and N-2 fluxes were small enough to consider these membranes as "barrier" films to the transport of those gases. Poly(GRTILs) may have use in applications where flow of those gases is not desirable. (C) 2007 Elsevier B.V. All rights reserved.