At the single molecular scale (less than 2 angstrom x 2 angstrom x 9.8 angstrom), the nonlinear electrical dipolar switching behavior from crystalline two-monolayer polyvinylidene fluoride films was measured using a scanning tunneling microscope (STM). The atomic structure of the polymer chain was clearly imaged by the STM. The nonlinear switching behavior at the single molecular scale appears as the hysteresis in the tunneling current-voltage relationship with switching onset voltage of 0.19 V/monomer. The nonlinear dipolar switching behavior at the single molecular scale has many potential applications including single molecular scale switching devices and re-writable non-volatile memories. (c) 2005 Elsevier B.V. All rights reserved.