This document details the synthesis and characterization of La(II) macrocyclic complexes using malonodihydrazide and various aldehydes, evaluating their physical and biological properties. The complexes were analyzed through methods like elemental analysis, UV-visible, and IR spectroscopy, and their antibacterial activities were tested against several pathogenic bacteria. The study highlights the significance of such complexes in bioinorganic chemistry and their potential applications in medicine.