In this study, we present a new concept in chemically stabilized ionic liquid membranes: an ionic liquid organosilica (ILOS) membrane, which is an organosilica membrane with ionic liquid-like properties. A silylated ionic liquid was used as a precursor for synthesis. The permselectivity, permeation mechanism, and stability of the membrane in the H 2/toluene binary system were then compared with a supported ionic liquid membrane. The membrane showed a superior separation factor of toluene/H 2 (>17,000) in a binary mixture system based on a solution–diffusion mechanism with improved durability over the supported ionic liquid membrane.