Light serves as a valuable external stimulus to control the structure and function of bio-relevant molecules with high spatiotemporal control in cellular and multicellular matrixes.1,2 We are developing light-responsive molecular tools for the study of intricate biochemical processes in both healthy and diseased cells and tissue. This talk will highlight our current research activities in the development of (i) light-responsive kinase inhibitors; and (ii) organelle-targeting caging groups which serve as photolabile protecting moieties, temporally masking the biological activity of the bioactive, and an organelle-targeting delivery system. The latter has been achieved by merging fluorescent caging groups with organelle-targeting ligands whereby fluorescence is used to monitor both sub-cellular localisation of the caged substrate prior to photoactivation and reporting that photoactivation has occurred.