Coupling reaction of 4-nitroaniline with 3-aminobenzoic acid provided the corresponding bidentate azo ligand. The prepared ligand was identified by Microelemental Analysis, 1H-NMR, FT-IR, and UV-Vis spectroscopic techniques. Treatment of the prepared ligand with Y(III) and La(III) metal ions in 1:3 M:L ratio in aqueous ethanol at optimum pH yielded a series of neutral complexes with the general formula of [M(L)3]. The prepared complexes were characterized by flame atomic absorption, Elemental Analysis (C, H, N), FT-IR, and UV-Vis spectroscopic methods, as well as conductivity measurements. The nature of the complexes formed were studied following the mole ratio and continuous variation methods; Beer's law obeyed over a concentration range of 1·10–4 – 3·10–4 M. High molar absorbtivity of the complex solutions were observed. In addition, the dyeing performance of the prepared ligand and their complexes were investigated on cotton fabric. The dyes were tested for light and detergent fastness. Biological activity of the ligand and complexes against three selected types of bacteria were also examined. Some of the complexes exhibited good bacterial activities