The exploration of underlying mechanisms and the rational development of ultra-sensitive, multi-stimuli responsive smart materials have become increasingly important due to their versatile applications, including AIEbased materials, reversible mechanochromic and acidochromic behaviors, and good chemical sensors. In this article, a novel benzophenone hydrazone-based ligand L3 was successfully synthesized and comprehensively characterized using a range of spectroscopic methods, along with single-crystal X-ray diffraction analysis. The ligand L3 crystallizes in a monoclinic crystal system with the space group P21. L3 displayed aggregation-induced emission behavior, accompanied by highly reversible responses to mechanical stimuli (mechanochromism) and acid exposure (acidochromism). The solid-state spectroscopic features and emission color changes were fully reversible through mechanical grinding and subsequent exposure to dichloromethane (DCM) vapors. Furthermore, the sensor L3 demonstrated reversible acidochromic behavior after successive addition of acid and base. L3 acted as a fast, highly sensitive, selective, and colorimetric and fluorometric sensor towards Cu2+ ions in aqueous solutions, exhibiting a 2:1 stoichiometric ratio and an ultra-low LOD value, 0.83 mu M. The practical utility of L3 was successfully demonstrated through Cu2+ detection in real water samples and test-kit application. Finally, bioimaging experiments confirmed its good cell permeability, negligible cytotoxicity, and effective sensing of intracellular Cu2+ in living cells.