To look for superior and safe high energy density compounds (HEDCs), 2,2 ',4,4 ',6 6 '-hexanitroazobenzene (HNAB) and its -NO2, -NH2, -CN, -NC, -ONO2, -N-3, or -NF2 derivatives were studied at the B3LYP/6-31G* level of density functional theory (DFT). The isodesmic reactions were applied to calculate the heats of formation (HOFs) for these compounds. The theoretical molecular density (rho), detonation energy (E-d), detonation pressure (P), and detonation velocity (D), estimated using the Kamlet-Jacobs equations, showed that the detonation properties of these compounds were excellent. The effects of substituent groups on HOF, rho, E-d, P, and D were studied. The order of contribution of the substituent groups to P and D was -NF2 > - ONO2 > -NO2 > -N-3 > -NH2. Sensitivity was evaluated using the nitro group charges, frontier orbital energies, and bond dissociation enthalpies (BDEs). The trigger bonds in the pyrolysis process for all these HNAB derivatives may be Ring-NO2, Ring-N=N, Ring-NF2, or O-NO2 varying with the attachment of different substituents. BDEs of trigger bonds except those of -ONO2 derivatives are relatively large, which means these compounds suffice the stability request of explosives. Taking both detonation properties and sensitivities into consideration, some -NF2 and -NO2 derivatives may be potential candidates for HEDCs.