Ni in the NU-1000 MOF for ethylene dimerization. Cr 3 MOF nodes incorporated into MIL-100 have shown moderate catalytic activity for ethylene oligomerization. nation site on Ni that serves as an active site for catalysis. The structural defects in trimetallic nodes within the MOFs offer an enticing opportunity for systematically investigating how the composition of these nodes influences the catalytic properties of the MOFs, thereby facilitating the establishment of structurefunction correlations. In this work, our focus lies on computationally delving into propylene oligomerization catalysis within these trimetallic MOF nodes using two distinct approaches. Firstly, we systematically alter the divalent metal, denoted as M in Fe 2 M, which acts as the catalyst's active site, spanning the first-row transition metal series from Sc to Cu, in order to unveil structure-function relationships. Furthermore, we substitute the trivalent spectator atoms, represented by Fe, with 3d-transition metals ranging from Sc to Cu, aiming to grasp the impact of spectator atoms on the catalyst's activity. Through scrutinizing the fluctuations in reaction energy barriers resulting from variations in active and spectator atoms, our goal is to gain insight into the influence of altering metal atoms on the activity of the catalyst. We employed DFT to monitor the reaction energy profile and then confirmed the rate-determining step using multireference calculations, specifically CASSCF/NEVPT2 due to the degenerate nature of the ground-state in the transition metal complexes.