Anilines 1a-h on reaction with potassium thiocyanate and bromine in acetic acid yielded substituted 2-amino[2,1-b][1,3]benzothiazoles 3a-h. The compounds 3a-h on reaction with ethyl acetoacetate and pheylidine acetoacetate, yielded, 2-methyl-4-H-pyrimido[2,1- b][1,3]benzothiazole-4-ones 4a-h and ethyl 4-phenyl-2-methyl-4H–pyrimido[2,1- b][1,3]benzothiazole-3-carboxylates 5a-h respectively. Pheylidine acetoacetate was conveniently prepared by employing Knoevnagel method using diethyl amine as catalyst. The newly synthesized compounds have been characterized by analytical data IR, 1H NMR, 13C NMR and mass spectral data. The compounds were then evaluated for antibacterial, antifungal, and anti-inflammatory activities.