A series of phosphinoyldithioformate compounds were synthesized from metathesis reactions of K[R2P(O)CS2], and R'nPbCl4-n and R’HgCl. The compounds isolated were characterized using infrared, UV and multinuclear NMR (1H, 13C, and 31P) spectroscopy. Structural diversity of these compounds is revealed through analysis of the infrared and NMR spectroscopy, where variable temperature 31P NMR spectroscopy data of 6 reveals non-rigid coordination behavior and an equilibrium of aniso bonded S,S 4-membered ring, and S,O bonded 5-membered ring bonding modes in [MeHg{S2CP(O)(Ph)2}], (6–6′). The crystal structure of 6′ shows the mercury atom in a T-shape geometry with S,O-bidentate coordinated ligand although room temperature NMR indicated the coordination to the mercury in 6 is non rigid in solution. Variable temperature 31P NMR spectroscopy yielded an average value of ΔG#6-6´ = 45.7 ± 1.7 kJ mol−1 for the temperature range of 190 K–283 K. The crystal structure of [Ph2Pb{S2CP(O)(Ph)2}2(H2O)], 1, reveals the lead atom in an unusual seven coordinate geometry with two S,O-bidentate coordinated ligands and axial phenyl groups. The seventh ligand is a water molecule bonded to lead forming a pentagonal plane.