The iodine(III) reagent, PhINTs, acts as a source of the nitrene fragment NTs, which undergoes facile insertion into the metal–sulfur bonds of a range of dithiocarbamate complexes. Addition of two equivalents of PhINTs to [M(S2CNR2)2] affords sulfido-amido complexes [M{SC(NR2)SNTs}2] (MNi, Cu), which insert two further nitrene fragments to afford zwitterionic tetraamido complexes [M{TsNSC(NR2)SNTs}2] (MCo, Ni, Cu). Crystallographic studies have been carried out on both types of complex allowing possible resonance hydrids of the new ligand types to be assessed.