Figure 1.

Operating principle of rotaxane-based mechanoluminophores. The interlocked assembly contains a fluorophore-carrying cycle (gray/green), a dumbbell-shaped molecule with a matching quencher (brown), and two stoppers (blue). Reactive groups (red) permit the integration into a polymer chain (gray). In the idle state, the cycle is preferably located around the quencher (top) and the fluorescence is quenched. The force-induced displacement of the two elements (bottom) causes a fluorescence turn-on.