The host-guest properties of cucurbit[7]uril (Q[7]) and bispyridinium ethylene derivatives have been studied by 1H NMR spectroscopy, UV–vis absorption spectra, and fluorescence emission analysis. The proton shifts associated with the guest encapsulated by the host suggested that the Q[7]-based [2]pseudorotaxane behaves like a fast molecular shuttle along the bispyridinium ethylene axle of the guest upon protonation and deprotonation of the terminal carboxylates. In particular, the distinct fluorescent response signals indicated that the bispyridinium ethylene moiety not only behaves as the axle component for the pseudorotaxane system, but also acts as an optical reporting unit during the host–guest complexation.