Bis(triphenyllead) compounds (Ph3Pb)2A [H2A = H2Ser ( = L-serine), H2Tyr ( = L-tyrosine), H2Phoser ( = phosphorylserine)], R3PbAcSer (HAcSer = O-acetylserine; R = Ph, Me) and Ph3SnAcSer have been prepared from R3MOH and the appropriate amino acids. From IR data it is inferred that all compounds are polymeric, and that (Ph3Pb)2A (A = Ser, Tyr) and Me3PbAcSer contain unsymmetrically bridging carboxylate groups and coordinating NH2. For (Ph3Pb)2Phoser a structure with a monodentate carboxylate group and intermolecular coordination of Pb by an NH2- and a P = O-group is proposed. The molecules of Ph3MAcSer (M = Pb,Sn) containing monodentate carboxylate groups are bridged by acetyl-C = O groups.