The synthesis of 5-acetyl-6-methyl-4-(1, 3-diphenyl-1H-pyrazol-4-yl)-3, 4-dihydropyrmidin-2 (1H)-thione was achieved by one-pot three-component synthesis using CaCl 2 in refluxing EtOH. The starting compound was utilized to synthesize a new series of 5-pyrazolyl; isoxazolyl; pyrimidinyl derivatives via the synthesized chalcone. Also, fused isoxazolo [5, 4-d] pyrimidine and pyrazolo [3, 4-d] pyrimidine were obtained by the treatment of 5-acetyl derivative with hydroxyl amine and/or hydrazine hydrate. Also, the thiosemicarbazide derivative was prepared and utilized to synthesize other new thiazole derivatives. The structures of all compounds have been established on the basis of their analytical and spectral data. All compounds was also evaluated for their antibacterial and antifungal activity against various strains of bacteria and fungi. Also, the anti-inflammatory activity of some of synthesized compounds was …