The aim of the work is the synthesis and characterization of the tridentate Schiff base (HL) containing (N and O) as donor atoms type (ONO). The ligand is: (HL) phenyl 2-(2-hydroxybenzylidenamino)benzoate This ligand was prepared by the reaction of (phenyl 2-aminobenzoate) with salicylaldehyde under reflux in ethanol and few drops of glacial acetic acid which gave the ligand (HL). The prepared ligand was characterized by (FT IR,UV–Vis) spectroscopy, Elemental analysis of carbon, hydrogen and nitrogen (C.H.N.) and melting point. The ligand was reacted with some metal ions under reflux in ethanol with (1 metal :2 ligand )mole ratio which gave complexes of the general formula: Pr III , Cr and III La III [M(L)2]Cl , M = Products were found to be solid crystalline complexes, which have been characterized , through the following techniques: Molar conductivity .Spectroscopic Method [FTIR and UV-Vis], additional measurement magnetic suspeliblity, Chloride content and Program [Chem. office–CS. Chem.–3D pro 2006]was used. Our research also includes studying the bio–activity of the (ligand and[La (L)2]Cl prepared against a kind of bacteria three of which were negative to gram dye some compounds (Proteus mirabilis, Klebsiella pneumonia, Escherichia coli), and one was positive to gram dye (Staphylococcus aureus). The [La(L)2]Cl showed inhibitive activity against some of bacteria under consideration. The magnetic moment coupled with the electronic spectra suggested an octahedral geometry for all the complexes .