Looking forward, we seek to increase the spatial resolution of the UC emission by combining chemical and optical means of control. In conclusion, we demonstrate a generalized approach to encapsulate blue-to-UV upconversion systems, which were deployed to conduct spatially controlled photochemical reactions in aqueous environments at depth. Specifically, two iridium complexes with excellent solubilities in organic solvents (e.g., toluene and TCB) were identified as sensitizers for blue-to-UV UC. The TTA-UC efficiencies of sensitizers ppy2 and tmd paired with the annihilator DBP in toluene led to both higher UC quantum yields and lower thresholds than a previously reported system, ppy3/DBP.