Two dinitrenes, p-dinitrenobenzene (1a) and 4,4’-dinitrenobenzophenone (2a), were generated photolytically in host crystals of p-dinitrobenzene and 4,4’-dinitrobenzophenone under cryogenic conditions. The dinitrenes proved to be extremely stable in the crystalline matrices at ambient temperatures persisting for more than a year (1a) without loss of ESR signal intensity. p-Dinitreneobenzene was found to be a ground state singlet by 820 cal/mol and the zero field splitting parameters determined by single crystal work are /D/=0.1539 and /E/=0.00683 cm(-1) 4,4’-Dinitrenobenzophenone was found to be a ground state singlet by 90 cal/mol suggesting that the carbonyl bond may be an antiferromagnetic exchange coupler.