Herein, we used a complex made up of a pH-controllable molecular switch and a molecular clip with TTF side walls. The molecular switch consisted of a [2]rotaxane with a dumbbell component that had dibenzylammonium and 4,4'-bipyridinium "stations" that were able to "lock up" the ring-shaped component known as a macrocycle. Under basic conditions the macrocyle moved to the bipyridinium station, displacing the molecular clip and dissociating the switch/clip complex. The sequential addition of a base and an acid induces migration of the macrocyclic unit of this [2]rotaxane from the NH2+ station to the bipyridinium unit and back again. In turn this controls the availability of the bipyridinium station for complexation with the molecular clip and results in significant colour changes that are clearly visible to the naked eye.