Stimuli-responsive luminescent materials are capable of changing their external appearances like emission color or behaviors upon facing force, heat, light, electricity etc. and have attracted considerable research interest in data storage, information security and fluorescent probes . Among them, mechanochromic (MC) luminogens based on organic molecules , metal complexes and polymers , exhibit tunable fluorescent properties in the presence of mechanical stimuli (e.g., shearing, pressing, grinding and rubbing). Their work mechanisms often refer to molecular-level changes in chemical structure (e.g., cleavage or formation of covalent bonds) , solid-state morphologies (e.g., crystal-to-amorphous , crystal-to-crystal , amorphous to crystal ), intramolecular conformation (e.g., conformational planarization) , and excited-state switching (e.g., from a locally excited (LE) state to an intramolecular charge transfer (ICT) state) . Although some mechanisms have been proposed, the relationship between fluorescent properties and various stimuli still remains ambiguous. Thus, making a clear picture for the underlying mechanism will be of significance for rational molecular design in the solid state.