In the present work, compound 3-arylidene amino-5-methyl-1,2,4-triazole (IIIa-c), required as starting material obtained in one-pot reaction by condensing 5-methyl-3-amino-1,2,4-triazole with different aromatic aldehydes. The required 5-methyl-3-amino-1,2,4-triazole was prepared from treatment of acetyl urea (I) with hydrazine hydrate, the compounds (IIIa-c) were converted to the corresponding [3-[5-methyl-1,2,4-triazol-2-yl]-2-arylthiazolidine-4-one (Va1-a3) and imidazoleine-4-one (Vb1-b3) by reacted it with thioglycolic acid and Glycine in absolute ethanol. The compounds (IIa-c) were converted also to 2-methyl-5-arylamino-5,6,-dihydroimidozo[2,1-b]-1,2,4-triazole (VIIIa-VIIIc) reacted with TCA then with aniline derivatives. The linear pathway strategy of all these synthesized compounds can be summarized in scheme (1).