Transmetalation occurs upon addition of HgCl₂ to (8-quinolyl)SnMe₃ to yield (8-quinolyl)HgCl. The molecule features a frustrated Hg–N Lewis pair; however the mercury(II) center showed low affinity for sulfur Lewis bases, S₈ or thiophene. In the presence of NH₄SCN, ligand redistribution led to R₂Hg. The molecule was found as linear or bent polymorphs, depending on the solvent of recrystallization. The geometry about Hg(II) in the bent polymorph is distorted trigonal prismatic that features a C–Hg–C angle of 84°, weak intramolecular Hg–N contacts, and two intermolecular η²-quinoline contacts in which the neighboring R₂Hg molecule participates as a bis-η²-bidentate ligand.