Diaryliminyls, generated in aqueous solution by oxidation of imino-oxyacetic acids with persulphate abstract hydrogen from primary and secondary ortho-alkyl substituents to give benzylic radicals. These mainly cyclise (before or after oxidation to the corresponding carbonium ions) to oxoanthryl and/or isoindoleninyl products which are further oxidised by the persuiphate. o-Methyl- and o-ethyl-diaryliminyls, generated by thermolysis of t-butyl peracetates in benzene react to give mainly the corresponding imine (and/or ketone by hydrolysis). Intramolecular hydrogen transfer occurs with o-isopropyl- and o-benzyl-diaryliminyls, the resulting benzyl radicals reacting further to give 10,10-dimethylanthrone and 1,3-diphenyl-2-(10-phenyl-9-anthryl)isoindole (and products derived therefrom), respectively. The e.s.r. spectra of several of the iminyls have been detected.