We calculated the energy barriers for C-C coupling and β-hydride elimination using multireference NEVPT2 calculations on top of the CASSCF wavefunction for four distinct cases. We considered Fe 2 Ni trimetallic MOF node since it has been experimentally synthesized. Additionally, we calculated the energy barriers for the Fe 3 MOF node to corroborate the experimental findings and the DFT predictions. Subsequently, Fe 2 Cu and Cr 2 Ni were considered as they exhibited the lowest barrier for the C-C coupling step among the variations of active and spectator atoms, respectively. The comparison of Gibbs free energies obtained from DFT and NEVPT2 is illustrated in Figure . The active orbitals considered for each case are shown in Section S3 (Table -33). It is to be noted that for the NEVPT2 energies, we incorporated the thermal correction obtained from DFT to the NEVPT2 electronic energies to derive the Gibbs free energies. For Fe 3 , NEVPT2 predicted C-C coupling step as the rate-determining step with a significantly high energy barrier, which is in agreement with experimental results and DFT predictions. Additionally, the barrier for β-hydride elimination is also similar to that obtained with DFT. However, for Fe 2 Ni, NEVPT2 identified C-C coupling as the kinetically relevant step whereas DFT suggested β-hydride elimination as the rate-determining step. Nevertheless, C-C bond formation is proposed to be the kinetically relevant step for propylene oligomerization, ethylene oligomerization and butene dimerization 52 mediated by Ni atom doped MOFs. Also, the difference between the two reaction barriers from DFT is only ∼6 kJ/mol. These suggest that DFT could inaccurately predict the rate-determining step when the energy difference between the two steps is small. In contrast, NEVPT2 consistently identifies the correct rate-determining step under these conditions. For Fe 2 Cu and Cr 2 Ni, both DFT and NEVPT2 consistently identified the β-hydride elimination and C-C coupling respectively as the rate-determining step with approximately similar barriers.