an information recording layer on a substrate provides a method of recording information by selectively opening the rings of dicyclopentadiene skeletons , thus recording information by forming cyclopentadiene skeletons . the information recorded by the method can be erased by the cycloaddition of cyclopentadiene skeletons . information can also be recorded or erased by incorporating or eliminating a metal ion from a selectively opened section of a ring of a dicyclopentadiene skeleton after forming an organic thin film comprising the dicyclopentadiene skeleton . alternatively , after the formation of an organic thin film comprising a cyclopentadiene skeleton , a heterocycle or a benzene ring , a metal ion is incorporated or eliminated from a section between at least two rings of the cyclopentadiene skeleton , the heterocycle or the benzene ring . thereafter , a metallocene skeleton or a skeleton analogous to the metallocene skeleton is formed or eliminated , thus recording or erasing information . the selective opening of a section of a dicyclopentadiene skeleton ring is carried out by heat or light . the readout of the information is performed by recognizing the cyclopentadiene skeleton , the metallocene skeleton , the skeleton analogous to the metallocene skeleton or the metal atom . the information recording layer of the invention is a chemically adsorbed monomolecular film with a thickness at the angstrom level .