Abstract: The esr spectra of a variety of bicyclo [2.2. 2] octane and bicyclo [2.2. l] heptane systems spin labeled with nitrobenzene anion radicals have been analyzed and assigned almost completely. The large couplings of homo-para-ex0 hydrogens and the small couplings of homo-meta-exo hydrogens in 6-nitrobenzobicyclene systems show that the exo couplings are undoubtedly affected by the spin densities of the nitrobenzene ring. It was ...