A thin film formed by an amphiphilic catenane is shown to exhibit bistable behavior. The film is grown by self-assembly from two different solutions onto a mica surface. Self-recognition of the solute molecules by the first monolayer of the adsorbed molecules drives the switch between two co-conformations, characterized by different polar character, which are nearly degenerate once deposited on the surface. The phenomenon takes the form of a wetting/dewetting transition and propagates the intramolecular change to the mesoscopic scale.