Reactivity of imidazolium ionic liquid with kaolinite and halloysite was studied. Intercalates of both clays gave unique spectral response in the THz region. Thermal analysis showed that halloysite-IL system has a higher thermal resistance. Repeated treatment of kaolinite-using the same IL increased its structural disorder. Disordered kaolinite resembled halloysite-like material with platy morphology.