PURPOSE: To permit the use of a laser beam obtd. from an AlGaAs semiconductor laser for recording and reproducing by incorporating bis[1,2-bis(3,4- dichlorophenyl)-1,2-ethenedithiolato(2-)-S,-S']nickel into a recording layer.
CONSTITUTION: The recording layer contains the bis[1,2-bis(3,4- dichlorophenyl)-1,2-ethenedithiolato(2-)-S,-S']nickel expressed by the formula I. The compd. I has excellent ability to prevent photodeterioration. The compd. expressed by the formula I may be used by coating a soln. prepd. by dissolving the compd. into a solvent directly onto a substrate, i.e., base and may be used in combination with a binder. The film thickness of the recording layer is preferably form 200Å to 1μm and is preferably in a 200W5,000Å range when the binder is not used. The compd. I is preferably used as a wet type and is also usable in dry process such as vapor deposition and CVD in some cases.