It was found that the photolysis of di(naphthyl-1-methyl)mercury (1) gives 1,2-dinaphthylethane (2) in heptane and benzene solvents and 2 and 1-methylnaphthalene in isopropanol and acetonitrile. Irradiation of 1 in carbon tetrachloride gives 2 and ClHgCH2C10H7 as primary reaction products, while the chloride is further photolyzed to 2. Quantum yields of the photolysis of 1 are high and equal to unity almost for all solvents. The chloride photodecomposition yield is an order of magnitude lower (0.1).