Ultrathin films of CuS and CuO have been obtained at the liquid-liquid interface by the reaction of copper cupferronate solution in toluene with Na2S or NaOH in aqueous solution. The films are generally single crystalline and around 40 nm thick. The thickness and crystallinity of the films are determined by the reactant concentrations and reaction conditions. The films have been characterized by electron microscopy and atomic force microscopy besides X-ray diffraction. Sonication of the films produces nanocrystals and nanorods which are also single crystalline.