A new method, limited growth of organometallic films in liquid phase, for preparation of Cu-TCNQ crystallites was adopted herein. Then the electrical properties of the Al/Cu-TCNQ film/Cu sandwichlike structures could be measured. The The transition between the highly resistive and conductive states with different parameters, such as threshold voltage, the shape of I-V curve, can be found depending on different average sizes of Cu-TCNQ grains. The the crystal boundaries may be one of the important factors contributing to the switching mechanism of Cu-TCNQ films has been suggested.