The complexes of La(III), Pr(III), Sm(III), Eu(III), Tb(III) and Dy(III) of general formula [Ln(L2)2(NO3)2]NO3 have been synthesized with Schiff base of (4-{[(3-hydroxyphenyl)imino]methyl}-1,5-dimethyl-2-phenyl-1,2-dihydro-3H-pyrazol-3-one) (L2) derived from 4-antipyrine carboxaldehyde and 3-aminophenol. The structure of complexes are proposed on the basis of analytical, spectral (FT-IR, UV-visible and 1 H NMR), magnetic and thermal studies. The molar conductance data indicate that the complexes are of 1:1 electrolytic nature. From spectral studies, the lanthanide ions were found to be eight coordinated in these complexes with two nitrate groups behaving in a monodentate manner. The photoluminescence properties of Sm(III), Eu(III), Tb(III) and Dy(III) complexes in dimethyl formamide were investigated. The Schiff base and its lanthanide(III) complexes were screened for their antibacterial activities against seven pathogenic bacteria: Staphylococcus aureus, Escherichia coli, Aeromonas hydrophila, Klebsiella pneumoniae, Vibrio cholerae, Salmonella typhimurium and Bacillus subtilis by agar disc diffusion method. Most of the complexes were found to exhibit potential activities against a number of pathogenic bacteria.