PURPOSE: To obtain photochromic naphthacenediones which cause a remarkable reversible color change from yellow to orange or red when irradiated with light of a specified wavelength and can be used as an optical information storage layer capable of cyclic writing and erasing.

CONSTITUTION: The photochromic naphthacenecliones are compds. of formula I and/or formula II [where each R is 6-14C aryl optionally substd. by alkyl, alkoxy, alkylthio, phenyl,, benzyl, CN, CF3, halogen or the like or one of two OR's is OH; R1-R. are each H, 1-18C alkyl, 1-18C alkoxy, 1-18C alkylthio, 1-18C alkylsulfinyl, phenyl, benzyl, CN, CF3, halogen, SO3R4, CO-R4, CO2R4 (R4 is H, alkyl, phenyl, benzyl or the like) or the like; and one of R1-R4 is a group of formula III (where X is a bonding group or X-CO(O) is a direct bond; and R5 and R6 are each H, halogen, alkyl or the like)]. The compds. of the formula I are converted into orange or red compds. of formula II when irradiated with light of 300-450 nm wavelength. The compds. of the formula H return to the compds. of the formula I when irradiated with light of 450 nm wavelength.