New monofunctionalised electrophilic and nucleophilic derivatives of 5,10,15,20-tetraphenyl-21H,23H-porphine (TPP) have been developed for controlled attachment to peptide amino and carboxyl side-chains, respectively. Reaction of 5-(4-aminophenyl)-10,15,20-triphenyl-21H,23H- porphine with 4-nitrophenyl chloroformate gave the corresponding nitrophenyl carbamate which coupled efficiently to lysine ε-amines. The aminophenylporphyrin, a poor nucleophile, was converted to a primary aliphatic amine by coupling with glycine. This glycylaminophenylporphyrin reacted readily with acyl azides derived from extended Glu side-chains. These systems offer access to novel polymeric porphinatomanganese(III) agents for contrast enhancement in MRI.