The PSVue™ product family of fluorescent imaging reagents is based upon the positively charged bis(zinc-dipicolylamine) (Zn-DPA) group that targets exposed anionic phospholipids such as phosphatidylserine (PS) on plasma membranes. It thus binds with high affinity to the surfaces of apoptotic and necrotic cells, as well as Gram-positive and Gram-negative bacterial cells under in vitro or in vivo conditions. In addition, PSVue is capable of imaging the necrotic cores of tumors in vivo. PSVue reagents allow for imaging capabilities in the NIR, long-UV, and visible light regions and are suitable for flow cytometry, fluorescence microscopy, and in vivo optical imaging.