Asymmetrical diarylmercury compds., e.g. p-MeOC6H4HgC6H4NMe2-p, were produced together with sym. products via a symmetrization process. The asym. products could not be isolated from the reaction mixt. and their existence was indicated through different analyses (m.p., IR, PMR, mass spectra, elemental analysis and DTA). The asym. products are unstable and disproportionate into two sym. compds. at elevated temps., and in org. solvents even at room temp. [on SciFinder(R)]