We reported recently in the Journal of Chemical and Pharmaceutical Research, 2012, 4(3):1511-1518, that Zn(II) coordinated with 2,5-diamino-1,3,4-thiadiazole with enhanced physical and biological properties. As part of our ongoing research for more effective antimicrobial drug, the same potentially bioactive ligand, 2,5-diamino-1,3,4- thiadiazole (L), derived from semicarbazide hydrochloride have been prepared and characterized. [(ML2)]; M= Fe(III), complex were prepared. Elemental, Infra-red, Ultraviolet/Visible, Magnetic moment, Atomic Absorption, Thin layer chromatography and molar conductance measurements have accomplished characterization of the complex. The IR data reveal that the ligand (L) behave as a tridentate neutral ligand.It coordinated to the metal ion via sulphur and nitrogen of the amines. The molar conductance data reveal that the chelates are non-electrolytes. From the Ultraviolet/Visible spectra and magnetic moment data, octahedral geometrical structure was proposed for the complex. Toxicological studies were carried out on male albino rats [Wistar strain], at the dosage level of 0.60mg/kg body weight thrice daily for 7days on the alkaline phosphatase (ALP) activities on rat kidney, liver and serum. Chelates do not showed toxicity in enzymes activities. In-vivo evaluation of the antimicrobial activities of the metal complex and the ligand showed greater activity, when compared to the parent compound, against some microorganisms