This invention is directed to the general method of transforming non-photoactive bioactive small molecule compounds of known structure and function into photoactive analogs of the small molecules which exhibit both photoactivity and the original biological targeting activity. The general method for the design of the photoactive analogs of the small molecules includes: (a) selecting a desired bioactive molecule; (b) identifying the region of the molecule that contains an aromatic or a heteroaromatic motif; and (c) either replacing said motif with a photoactive functional group of similar size, or modifying said motif to make it photoactive. Other aspects include photoactive analog compounds and photodiagnostic and phototherapeutic uses thereof.