Ab initio molecular orbital theory and density functional theory have been applied to study the isoelectronic-liganded NiL2 (L = N-4(2-), C4H42-, and C2O22-) sandwich complexes at the MP2/6-31G*, B3LYP/6-31G*, B3LYP/6-311+G*, and BHLYP/6-311+G(3df,3pd) levels of theory. The stable structure for Ni(N-4)(2) is a staggered conformer with D-4d symmetry. The dissociation barriers for one N-2 elimination and two N2 eliminations for Ni(N-4)(2) are 37.1 and 84.9 kcal/mol, respectively, at the B3LYP/6-31G* level of theory, which suggest that Ni(N-4)(2) is kinetically stable enough to resist dissociation. The calculated reaction energies for the dissociation of Ni(N-4)(2), Ni(C4H4)(2), and Ni(C2O2)(2) at the B3LYP/6-31G* level of theory suggest that both Ni(N-4)(2) and Ni(C2O2)(2) are high-energy species; however, Ni(C4H4)(2) is not.