Corrosion damages all materials, necessitating replacement and inspection related expenses. Thus, the demand has increased for new corrosion inhibitor materials. The ratios of corrosion inhibition of materials are different, but organic compounds have high efficiency in aqueous corrosion inhibition for various alloys and metals. This efficiency can increase in the presence of O, N and S. The molecule provides great inhibition with the presence of both S and N atoms in the same compound. This paper investigates the 1, 3, 4-thiadiazole molecule and electronic structure of several organic compounds such as R1 and R2 which consist of different substituent groups. They were united to the ring of 1, 3, 4-thiadiazole to provide nine different derivatives. Quantum computations (density functional theory, DFT) at 6-311G++ (d, p) basis set and Becke’s three parameters hybrid (B3LYP) level were performed using Gaussian program. The purpose of this study is to determine the chemical behaviour of several heterocyclic organic compounds and to understand the process of the corrosion inhibition.