A polarization-dependent device is provided that includes organic materials having electric dipoles. The polarization-dependent device comprises: (a) a source region and a drain region separated by a channel region having a length L, formed on a substrate; (b) a dielectric layer on at least a portion of the channel region; and (c) a molecular layer on the dielectric layer, the molecular layer comprising molecules having a switchable dipolar moiety. Addition of a gate over the molecular layer permits fabrication of a transistor, while omission of the gate, and utilization of suitable molecules that are sensitive to various changes in the environment permits fabrication of a variety of sensors. The molecular transistor and sensors are suitable for high density nanoscale circuits and are less expensive than prior art approaches.