Arylazopyridines (Haap,1) are mercurated by Hg(OAc)2 in methanol followed by LiCl addition. Two classes of compounds are identified: Hg(Haap)Cl2 (2), a simple coordination compound of tetrahedral geometry, and organomercury compounds, Hg(aap)Cl(3). The compounds are characterised by elemental analyses, IR and1H NMR spectra. The NMR results suggest that mercury is directed to the C-5 position (meta to pyridine-N) in the pyridine fragment of the ligand. This assumption is supported by net atomic charge calculation using the MNDO method.