| Summary: | Coordination complexes (<b>1</b>–<b>4</b>) of 2-amino-4-methylbenzothiazole and 2-amino-3-methylpyridine with Cu(CH<sub>3</sub>COO)<sub>2</sub> and AgNO<sub>3</sub> were prepared and characterized by UV/Vis and FT-IR spectroscopy. The molecular structure for single crystals of silver complexes (<b>2</b> and <b>4</b>) were determined by X-ray diffraction. The coordination complex (<b>2</b>) is monoclinic with space group <i>P</i>21/c, wherein two ligands are coordinated to a metal ion, affording distorted trigonal geometry around the central Ag metal ion. The efficient nucleophilic center, i.e., the endocyclic nitrogen of the organic ligand, binds to the silver metal. Ligands are coordinated to adopt <i>cis</i> arrangement, predominantly due to steric reasons. The O(2) and O(3) atoms of the <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mi>N</mi><msubsup><mi>O</mi><mn>3</mn><mo>−</mo></msubsup></mrow></semantics></math></inline-formula> group further play an important role in such type of ligand arrangement by hydrogen bonding with the NH<sub>2</sub> group of ligands. Complex (<b>4</b>) is orthorhombic, <i>P</i>212121, comprising two molecules of 2-amino-3-methylpyridine as ligand coordinated with the metal ion, affording a polymeric structure. The coordination behavior of the ligand is identical to that in complex <b>2</b>, wherein ring nitrogen is coordinated to the metal center and bridged to another metal ion through an NH<sub>2</sub> group. The resulting product is polymeric in nature with the Ag metal in the backbone and ligand as the bridge. Compounds (<b>2</b>–<b>4</b>) were found to be luminescent, while <b>1</b> did not show such activity. All compounds were screened for their preliminary biological activities such as antibacterial, antioxidant and enzyme inhibition. Compounds exhibited moderate activity in these tests.
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