Abstract Metallo-β-lactamases (mβl) and phosphotriesterase (PTE) are zinc (II) enzymes, which hydrolyze the β-lactam antibiotics and toxic organophosphotriesters, respectively. In the present work, we have synthesized a few asymmetric phenolate-based ligands by sequential Mannich reaction and their corresponding zinc (II) complexes. These zinc (II) complexes were studied for their mβl and PTE activities. It is shown that the zinc (II) ...