Proton pump inhibitors (PPIs) are a type of drugs that function on the cells by reducing the secretion of acid which is attached to the stomach. They act irreversibly by blocking the hydrogen/potassium adenosine triphosphatase enzyme system (the H + /K + ATPase or, more commonly, the gastric proton pump) of the gastric parietal 1,2 cells. They are substituted benzimidazoles which is applied for the remedy of acid-related syndromes, including gastroesophageal reflux disorder (GERD) and peptic sore disease. These are lipophilic weak bases which span the parietal cell membrane and enter the acidic parietal cell canaliculus . They have a basic fundamental structure which differs only in the sort of substituents group located on the pyridine and benzimidazole rings. This is shown by the following formula: Acidic environment is required for PPI to undergo rearrangement for the active form. The PPIs become protonated in the acidic environment, that give rise to activated sulphonamide form which ties covalently with the H + /K + ATPase enzyme. This causes irreversible inhibition of acid excretion by the pump . Therefore these drugs are really helpful for the remedy of acid caused inflammation condition as well as abscesses of the stomach and duodenum, gastroesophageal reflux illness, all produced by stomach acid . Omeprazole is one of the well-known proton pump Because of the significance of drugs and their compounds , it is appropriate to make the metal complexes of omeprazole and investigate their properties . It is likewise recognized that complexes with metal show a crucial function in biological actions of medicine. In numerous circumstances, drugs having complexes with metal are more effective compared to the original drug itself. Interpretation of physical and chemical characteristics of complexes of drugs should be valuable in defining their biotic activities . This report presents, synthesis and physicochemical description of zinc(II), cadmium(II), mercury(II) and copper(II) complexes of omeprazole. (Shimadzu, Japan) over the span of 4000-400 cm -1 using potassium bromide pallets. The ultraviolet-visible spectra of the compounds were verified by means of a UV-Visible spectrometer of Model UV-1800 (Shimadzu, Japan), using wavelength spanning from 200 to 1100 nm in methanolic solvent. Thermal analysis (TGA) of compounds was performed with TGA-50 thermogravimetric analyzer (Shimadzu, Japan), quasi-static thermal analysis (QSTG) experiment was done in a CARBOLITE calibrated muffle furnace of the type CWF11/5 and the differential scanning calorimetric (DSC) examination was performed with DSC-60 analyzer (Shimadzu, Japan). Data related to magnetic susceptibility of the compounds was estimated by the SHERWOOD SCIENTIFIC Magnetic Susceptibility Balance (M.S.B.) of model Magway MSB Mk1, Cambridge, England.