A series of Imidazo[2,1-b]thiazole pyrmidine derivatives (3a-g-) were designed, synthesized from imidazo[2,1-b]thiazole chalcone derivatives. (2a-g) and Urea in PEG-400 and evaluated for their anti-bacterial potency. Characterization of newly synthesized compounds was done using IR and 1H NMR and Mass spectroscopy. Further Imidazo [2,1-b]thiazole pyrimidine derivatives were subjected to check their anti-bacterial activities against four different strains, viz two Gram +ve bacteria Staphylococcus aureus & Bacillus subtilis and two Gram -ve bacteria Escherichia coli & Pseudomonas aeruginosa by using Well diffusion method for the determination of zone of inhibition as antibacterial activity of the synthesized compounds. KEY WORDS: Imidazo[2,1-b]thiazole Chalcones, Imidazo[2,1-b]thiazole 4-carbaldehyde, Imidazo[2,1-b]thiazole pyrimidines, PEG-400, anti-inflammatory activity