Semiconductor quantum dots (QDs) are attractive for potential use as photosensitizers for a variety of applications. These nanomaterials have very high absorption cross-sections and often display strong photoluminescence (PL). Furthermore, QD absorption and emission spectra can be tuned simply by varying their size, and QD surfaces can be modified to access multiple sites for attaching potential acceptors as well as other functionalities. Here we provide an overview of recent studies concerned with the photosensitization of transition metal centers and other acceptors. Particular focus is directed towards potential therapeutic applications and to our own interest in the delivery of small molecule bioregulators to physiological targets. Studies that have addressed factors that control likely energy and charge transfer processes between QD donors and acceptor molecules are also discussed. Understanding the mechanisms of these photosensitization processes can provide design guidelines for successful applications.