In the current investigation, two series of 2-amino thiazole derivatives were prepared. The first series involved synthesis of (Z)-3-(thiazol-2-ylimino)indolin-2-one (A1) as Schiff base derivatives of 2-amino thiazole and isatin, then synthesis of compounds A5, A6 and A7 as five membered rings (imidazolidins) by using different amino acids, and synthesis of compounds A3 and A4 as seven membered rings (1,3-oxazepine-di-one) by using maleic and phthalic anhydrides respectively. In the second series, 2-amino thiazole was treated with acetyl acetone to form (2E,4E)-N2,N4-di(thiazol-2-yl)pentane-2,4-diimine (A2) as di-Schiff base derivatives, and finally the preparation of imidazolidin (A8) by using 2 mol of tyrosine and preparation of tetrazole derivative (A9) by using 2 mol of sodium azide. The biological study for the above two series indicated that both gram-negative and gram-positive activities were noticed.