A molecular crossbar latch is provided, comprising two control wires and a signal wire that crosses the two control wires to form a junction with each control wire. The latch further includes a control mechanism for controllably electrically connecting and disconnecting signal input to the latch, thus allowing the input to change its logic value after the signal is latched while the signal wire retains its latched value. Each junction forms a switch, the junction having a functional dimension in nanometers. The crossbar latch permits latching a logic value on the signal wire. Further, methods are provided for latching logic values in a logic array, for inventing a logic value , and for restoring a voltage value of a signal in a nano-scale wire.