New eight lanthanide metal complexes were prepared. These complexes were characterized by elemental analysis, molar conductivity measurements, spectral analysis ( 1 H NMR, FT-IR, UV–vis), luminescence and thermal gravimetric analysis. All Ln(III) complexes were 1:1 electrolytes as established by their molar conductivities. The microanalysis and spectroscopic analysis revealed eight-coordinated environments around lanthanide ions with two nitrate ligands behaving in a bidentate manner. The other four positions were found to be occupied with tetradentate L III ligand. Tb–L III and Sm–L III complexes exhibited characteristic luminescence emissions of the central metal ions and this was attributed to efficient energy transfer from the ligand to the metal center. The L III and Ln–L III complexes showed antibacterial activity against a number of pathogenic bacteria.