In this study, 4-hydroxyphenyl-3H-1,2,4-triazol-3-one derivatives (la-d), cyanomethoxyphenyl-3-alkyl/aryl-5-oxo-4,5-dihydro-1H-1,2,4-triazol-acetonitriles (2a-d) and bis amino-1,3,4-thiadiazol-5-alkyl/aryl-2,4-dihydro-3H-1,2,4-triazol-3-one (3a-d) were synthesized. The new compounds were characterized by elemental analyses, IR, H-1 NMR, C-13 NMR and mass spectral studies. The molecular structure of compound 2c was determined by X-ray diffraction. Vibrational data, H-1 NMR and C-13 NMR chemical shifts of compound 3 b were obtained by DET/B3LYP/6-311++G(d,p) method and theoretical spectral data were compared with the experimental ones. Furthermore, Gauswiev 5.0 was used to visualize the results of the computation MEP surface for compound 3 b. (C) 2020 Elsevier B.V. All rights reserved.