Dimerization and polymeric self-arrangement of [HgII(Py)2(PhN2C6H4NNNC6H4R)2] (Py = pyridine; R = NO2) through reciprocal metal-η2-arene π-interactions and non-classical C-H⋯O bonding: Synthesis and X-ray characterization of a polyaryl asymmetric-

3-(4-Phenyldiazophenyl)-1-(4-nitrophenyl)triazenide reacts with Hg(CH3COO)2 and pyridine to give {[HgII(Py)2(PhN2C6H4NNNC6H4R)2]2}n (Py = pyridine; R = NO2), the first reported HgII-Py complex with two coordinating pyridine molecules. The tectons [HgII(Py)2(PhN2C6H4NNNC6H4R)2] are linked to pairs as centrosymmetric dimers through reciprocal metal-η2-arene π-interactions. The dimers are assembled by translation on the ac plane to unidimensional chains linked through non classical C-H⋯O hydrogen bonds.