Polymer mechanochemistry is an emerging research area at the intersection between chemistry and materials science, with fascinating applications such as force-triggered release of small molecules and the manufacturing of mechanochromic materials. At the heart of many functional polymers are mechanophores, i.e., molecular constituents of a polymer that respond to stretching forces by significant structural changes, e.g., the rupture of covalent bonds. Typically, mechanophore activation is a one-way process. Once a covalent bond is activated, a desired response is achieved, e.g., a color change in the material or the release of an organic molecule, and restoring a mechanophore to its original form is usually not possible.