Porphyrins are tetrapyrrole ring structures which are metal chelating and often found in the active sites of enzymes involved in redox reactions. We have demonstrated that porphyrins alone may act as mediators in the transfer of electrons to or from various functional groups under a range of reaction conditions. One such application is the porphyrin-catalyzed reduction of nitroaromatics to the corresponding amines. For nitroaromatic components of munition wastes such as ’pink water," porphyrin pretreatment can render the wastes safer to handle and more amenable to biotreatment.