Because Of their extended conjugated bond network, aromatic compounds generally have higher redox stability than less saturated compounds. We conjectured that ionic liquids (ILs) consisting, of aromatic heterocyclic anions (AHAs) may exhibit improved radiation and electrochemical stability. Such properties are important in, applications' of these ILs as diluents in radionuclide separations and electrolytes in the electric energy storage devices. In this Study, we systematically examine the redox, chemistry of the AHAs. Three classes of these anions have be-en studied: (i) simple 5-atom. ring AHAs, such as the pyrazolide and triazolides, (ii) AHAs containing an adjacent benzene ring,:and (ill), AHAS containing electron-withdrawing-groups that were introduced to reduce their basicity and interaction with metal ions. It is shown that fragmentation in the reduced aid oxidized states of these AHAs does not generally occur, and the two main products, respectively, are the 1,1 atom adduct and the imidyl radical. The latter species occurs either as an. N sigma-radical or as an N pi-radical, depending on the length of the N-N bond, and the State that is Stabilized in the solid matrix-is frequently different from that having the lowest energy in the gas phase. In some instances, the formation-of the sandwich pi-stack dime radical anions has been observed. For trifluoromethylated anions, H adduct formation did not occur; instead, there was facile loss of fluoride from their fluorinated groups. The latter can be problematic in nuclear separations, but beneficial in batteries. Overall, our Study Suggests that AHA-based ILs are viable candidates for use as radiation-exposed diluents and electrolytes.