Described are novel compounds of the Formula (I), their derivatives, analogs, tautomeric forms, regioisomers, stereoisomers, polymorphs, solvates, intermediates, pharmaceutically acceptable salts, pharmaceutical compositions, metabolites and prodrugs thereof. These compounds are effective in lowering blood glucose, serum insulin, free fatty acids, cholesterol, triglyceride levels； treatment of obesity, inflammation, autoimmune diseases such as multiple sclerosis, rheumatoid arthritis； treatment and/or prophylaxis of type II diabetes. These compounds are more particularly dipeptidyl peptidase (DPP IV) inhibitors.
