The reactions of di(2-thienyl)mercury, 2-thienylmercury chloride and 2-furylmercury chloride with a variety of nitrogen-and phosphorus-containing ligands have been studied. The presence of the electron-withdrawing heteroatoms results in these mercurials being stronger acceptors than the corresponding phenylmercury compounds. The complexes have been characterized by elemental analysis, melting points, infrared, and 199 Hg NMR spectroscopy. 2,9-Dimethyl-and 3,4,7,8-tetramethylphenanthroline form 1 : 1 chelate complexes, as does 1,2-bis(diphenylphosphino)ethane, whereas ethylenediamine and 2,2 -bipyridyl do not form complexes. Though non-chelating ligands such as 2,4 -and 4,4 -bipyridyl do not form complexes, bis(diphenylphosphino)methane forms 1 : 2 complexes in which the ligand bridges two mercury atoms. Monodentate ligands, such as triphenylphosphine, cause disproportionation of the organomercury chloride. 2-Thienylmercury chloride forms a 4 : 1 complex with 4,4 -dipyridyl disulfide in which it is believed that a molecule of the organomercurial is coordinated to both of the nitrogen and both of the sulfur atoms.