Magnetic susceptibility and magnetisation measurements were performed on a powdered crystalline sample restrained in eicosane in the temperature and fields ranges T = 2-300 K, B = 0.1 T and T = 2-6 K, B = 0.5 -7.0 T, respectively, using a Quantum Design MPMS XL SQUID magnetometer equipped with a 7 T dc magnet. The observed paramagnetic susceptibilities were corrected for diamagnetic contributions using Pascal's constants. correlations on model 1C (Figure ) to check the dependence of the magnetic exchange interaction on the average Ni-O distance and average Ni-O-Ni angle. We have made several mono-and dimetallic models (1D-1G, Figure ) from complex 1 to estimate the zero field splitting parameters for each Ni II centre using the ORCA software suite (version ORCA 4.0). The zeroth-order regular approximation (ZORA) method together with the ZORA contracted version of the basis set (ZORA-def2-TZVP for Ni, Zn and ZORA-def2-SVP for rest of the elements) have been used. The calculation further utilised the resolution of identity (RI) approximation with the auxiliary def2-TZVP and def2-SVP coulomb fitting basis sets. During state-average complete active space self-consistent field (SA-CASSCF) calculations, we have included eight electrons in five d-orbitals (CAS (8 electrons/5 3d-orbitals)) in the active space. Ten triplet and fifteen singlet roots are considered during CASSCF calculations. To consider the dynamic correlation, we have performed 2 nd order N-electron valence perturbation theory (NEVPT2) calculations. We have employed integration Grid 6 for the Ni and Zn ions, and Grid 5 for remaining elements.