Abstract: The present invention relates to pyridinone based azo dyes and/or of anionic azo metal complex dye salts made thereof with cationic basic yellow dyes, which are characterized by an unsaturated bond in beta-position to the endocyclic N atom of the pyridinone, and to their use in optical layers for optical data recording, preferably for optical data recording using a laser with a wavelength up to 450 nm. The invention further relates to a write once read many (WORM) type optical data recording medium capable of recording and reproducing information with radiation of blue laser, which employs pyridinone based azo dyes and/or anionic azo metal complex dye salts made thereof with cationic basic yellow dyes, which are characterized by an unsaturated bond in beta-position to the endocyclic N atom of the pyridinone, in the optical layer.