This book surrounded with the microwave assisted synthesis of some new 3-substituted-pyrazol-1H-pyrazolo[1,2-b]phthalazine-5,10-dione derivatives and investigation of their antimicrobial activity. The one-pot three-component, microwave assisted condensation reaction of 3-substituted-1H-pyrazole-4-carbaldehyde 1a-d with cyano-active methelene 2a-d and 2,3-dihydro-1,4-phthalazinedione 5 proceeded effortlessly in ethanol in presence of triethyl amine (TEA) as a catalyst to give corresponding 3-substituted-pyrazol-1H-pyrazolo[1,2-b]phthalazine-5,10-dione derivatives in good to excellent yields. So, it is admirable to express brief about synthetic and biological significance of the phthalazine.