Three new 1,3,4-oxadiazole, 1,3-thiazolidine and 1,2,4-triazole derivatives were obtained starting from furan-2-carbohydrazide. Then, 1,2,4-triazole compound was converted to the corresponding Mannich bases using several secondary amines including piperidine, piperazine, morpholine or thiomorpholine moiety. The synthesis of 5-(furan-2-yl)-4-{[(4-methoxyphenyl)methylidene]amino}-4H-1,2,4-triazole-3-thiol (XIII) was performed starting from furan-2-carbohydrazide by three steps. The structures of the synthesized compounds were well characterized by elemental analyses, IR, 1H NMR, 13C NMR and mass spectral studies. Newly synthesized compounds were screened for their antimicrobial activities and some of them displayed activity against the tested microorganisms.