A molecular wire crossbar memory (MWCM) system is provided. The MWCM comprises a two-dimensional array of a plurality of nanometer-scale devices, each device comprising a junction formed by a pair of crossed wires where one wire crosses another and at least one connector species connecting the pair of crossed wires in the junction. The connector species comprises a bi-stable molecular switch. The junction forms either a resistor or a diode or an asymmetric non-linear resistor. The junction has a state that is capable of being altered by application of a first voltage and sensed by application of a second, non-destructive voltage.