OPTICAL INFORMATION-RECORDING MEDIUM

PURPOSE:To contrive higher sensitivity and stability of an optical information- recording medium used for writing and reproducing information by semiconductor laser, by providing a recording layer comprising a specified organic coloring matter. CONSTITUTION:A recording layer is provided which comprises an organic coloring matter of formula I, wherein R1 is a 1-6C alkyl, aralkyl or phenyl, R2 is H, a halogen, 1-6C formula II (Ph: phenyl) or formula III (R3: a 1-6C alkyl), Y is -R4SO3, Y' is -R4SO3Na or -R4SO3NH(R5)3, and Z is benzene ring added to the benzene ring constituting indole. Since the organic coloring matter has two five-membered rings introduced into a methine chain, it has excellent preservation stability and characteristics of deterioration on reproduction. In addition, the coloring matter has excellent moisture resistance, since the benzene ring as Z is added to the benzene ring constituting indole. Further, the coloring matter has excellent chemical stability, solubility in solvents and wettability for a substrate, since Y such as a sulfoalkyl is introduced into indole.