A number of new bis-intercalating anthracycline antibiotics, analogs of daunomycin, have been designed and synthesized in our collaborator's laboratory. The rational design of these new compounds was based upon the geometry of monomeric anthracyclines bound to DNA oligonucleotides observed in high-resolution crystal structures. Monomeric units of daunorubicin have been linked through their reactive 3' NH2 substituents on the daunosamine moieties to form these bisanthracyclines. Since differential intracellular binding complexes can be distinguished and quantitated by fluorescence lifetime analyses, we will use this approach to detect binding of these new agents to different subcellular components. From such determinations those drug complexes responsible for cytotoxicity may be ascertained. The design of new potential anticancer agents based on known structural principles and binding properties can be used to produce a compound with significantly increased DNA binding affinity and with interesting biological activity.