Angiotensin II receptor antagonists, also known as angiotensin receptor blockers (ARBs), AT1-receptor antagonists or sartans, are a group of pharmaceuticals which modulate the renin-angiotensin-aldosterone system. These substances are AT1-receptor antagonists - that is, they block the activation of angiotensin II AT1 receptors.Blockade of AT1 receptors directly causes vasodilation,reduces secretion of vasopressin, reduces production and secretion of aldosterone, amongst other actions - the combined effect of which is reduction of blood pressure. Irbesartan molecule has pyrazolidinone structure and many thiazolidinone derivatives, are reported for their interesting profile of activities. As these two compounds could prove isosteric with the moiety present in Irbesartan, we thought it is worthwhile to condense these two moieties and form their Mannich bases as the resultant compound may act as angiotensin II antagonists. For this reason Mannich bases were prepared and evaluated fortheir activity.