Unrestricted DFT based calculations of the hyperfine tensors were performed on the optimized structures using the ORCA 5.0.1 suite of programs . Relativistic effects were included with ZORA Hamiltonian at SR and SO levels. During the calculation of EPR properties, SOC effects were introduced through coupled-perturbed self-consistent field (CP-SCF) procedure with convergence tolerance at 10 -4 scale and together with spin-orbit mean-field (SOMF) representation of the SOC operator as implemented in ORCA . To consider the DFT exchangecorrelation and basis set effects on the hyperfine tensors, a set of DFT functionals and basis sets were considered as mentioned later. The SO-CAS based hyperfine tensor calculations were also performed in ORCA but includes the relativistic effects at DKH2 level of theory with the DKH-TZVP basis set for metal center and IGLO-III basis set for ligand atoms. The so-called "picture-change" (as briefly outlined in the SI) of the hyperfine operators at the ZORA and DKH level of theory was considered and a finite nuclear model was employed. The dia-and paramagnetic contributions to the orbital chemical shielding includes gauge-including atomic orbital (GIAO) and ZORA treatment of atomic integrals .