In contrast, focused blue light enabled photolysis primarily at the focal point in a solution containing ppy2/PPO micelles (Fig. , bottom row), which became more apparent after background subtraction (Fig. , bottom row). In summary, encapsulated blue-to-UV upconversion systems offer exquisite control over the volume and location of UV-triggered photochemical reactions. This technology enables opportunities for the precise photochemical manipulation of light-responsive materials that are currently inaccessible with direct excitation.