Compositions of dendrimer-photosensitizer complexes including therapeutic molecules, and methods for their synthesis and use are disclosed. The therapeutic molecules and the photosensitizers are each covalently attached to the dendrimer at its end-groups, essentially randomly. Upon exposure to radiation of a suitable wavelength, the photosensitizers are activated to break up the dendrimer structure and thus release the therapeutic molecules. In a preferred embodiment, the end-groups of the dendrimer are replaced with or covalently connected to therapeutic molecules and photosensitizers. In a further preferred embodiment, targeting molecules may also be attached to the dendrimer to create a more accurate treatment. The present invention is especially useful for medical applications, where therapeutic molecules can be delivered to body areas for treatment of a variety of diseases without risk of premature release in the body, due to the strength and stability of the bonds between the end-groups and the photosensitizers and therapeutic molecules.