A versatile bioinspired metallocatalyst [Ni2L2(NCS)(Ac)(H2O)0.5(MeOH)0.5]·1.25H2O (HL=2-((E)-(2-(pyridin-2-yl)ethylimino)methyl)-4-chlorophenol) has been synthesized from a Schiff-base ligand and characterized as reported earlier (Sanyal et al., 2016). It portrays catecholase activity as an oxygen dependent enzymatic radical catalysis under completely aerobic conditions (λmax=375nm, ε=1900M−1cm−1) against the model substrate 3,5-di-tert-butylcatechol (3,5-DTBC). Interestingly, Michaelis-Menten analysis of pseudo first-order reaction kinetics establishes that DMF medium provides a better catalytic pathway for catecholase activity (kcat=2.8×10−3s−1) than acetonitrile (9.11×10−4s−1) under excess substrate conditions. Cell viability study, drug uptake assay, reactive oxygen species (ROS) formation, alteration of mitochondrial membrane potential (MMP), apoptosis study and DNA fragmentation demonstrates a significant dose dependent anti-leukemic activity on KG-1A (AML) and K562 (CML) cell lines. Notably, outstanding anti-bacterial property was also observed on multi-drug resistant E. coli and S. aureus bacteria.