Photoresponsive molecules are widely used in various fields, including materials chemistry and chemical biology. Such molecules exhibit drastic changes in chemical structure or specific bond cleavages in response to external photostimulation. For instance, azobenzene, which undergoes cis-trans isomerization upon photoirradiation, is a representative photoresponsive chemical structure widely used in photomanipulation techniques. Other unique photoresponsive molecules, such as nitrobenzene-and coumarin-linked derivatives, are known as photocleavable molecules, which exhibit specific bond cleavages triggered by photoirradiation. These photocleavable molecules are valuable tools, particularly in the fields of cell and chemical biology. For instance, caged compounds composed of photocleavable molecules can activate biologically inert signaling molecules via photostimulation. These compounds are useful in light-stimulated drug delivery systems, enabling highly controlled drug release with precise spatial and temporal resolution. Coumarin-based photocleavable molecules provide a significant advantage over nitrobenzene-based derivatives due to their structural flexibility, enabling precise control of absorption wavelength and broader applicability across experimental setups. Typical nitrobenzene-based photocleavable molecules are difficult to induce bond cleavage at wavelengths longer than 400 nm because of the limited chemical modifications of their benzene ring. In contrast, coumarin-based photocleavable molecules, which are relatively easier to modify and have an expandable π structure, allow for the arbitrary selection of wavelengths in the visible light region. Despite the advantages of coumarin-based derivatives, their persistent and widespread use is hindered by lower photocleavage efficiency and potential hydrolytic instability. The photocleavage efficiency of coumarin-based molecules correlates with the stability of the anionic species generated in the excited state of these molecules under photoirradiation. Although ester bonds are often incorporated into the structure to stabilize the anionic species, they are potentially unstable against hydrolysis and easily degraded in aqueous and cellular environments. On the other hand, Schulte et al. recently reported a novel and effective approach for enhancing the photocleavage efficiency of coumarin-based derivatives by stabilizing the cation species generated in the excited state. They further discussed the escape model of contact ion pairs, which is influenced by environmental conditions and payload size. While these studies have provided valuable insights, the structural design of photocleavable chemical tools feasible for cell and chemical biology remains unexplored. New structural guidelines for creating highly functional molecules should considerably elevate the foundation of photomanipulation technologies for flexible applications in cell and chemical biology. In this study, we developed a novel coumarin-based photocleavable molecule that exhibits both effective photocleavage properties and high hydrolysis resistance. Our approach involved introducing silyl groups into coumarin-based molecules to achieve steric protection of carbonyl bonds and stabilization of cationic species in the excited state (Figure ). Incorporating reactive functional groups into the molecular structure can impair overall activity. An important molecular design guideline for chemical biology tools is that they should be sufficiently stable in cellular environments and respond selectively and rapidly to desired stimuli. Considering that the intracellular environment is aqueous, incorporating chemically unstable structures prone to hydrolysis is impractical. Additionally, these molecules must exhibit high resistance to metabolic enzymes (both oxidative and hydrolytic), reactive chemical species such as glutathione, and reactive oxygen species present at high concentrations in cells. With these constraints in mind, we designed a coumarin-based photocleavable molecule with a chemically stable trimethylsilyl (TMS) group. The remotely introduced TMS group sterically protects the hydrolysis-sensitive carbonyl bond and simultaneously stabilizes the photoexcited cationic species through the β-silyl effect, thereby enhancing photocleavage efficiency. Further, we applied our design to create a biomaterial that enables the photoinduced cleavage of proteins from a solid phase material under low-intensity light conditions.