In this study, computational calculations of 1,2-dimethyl-3-[(5-methylsulfanyl-1,3,4-thiadiazol-2-yl)diazenyl]-1H-indole have been carried out using the Becke-3-Lee–Yang–Parr density functional methods with 6-311+G(d,p) basis set. The geometry optimization and fundamental frequencies of the most stable configuration have been calculated. The FTIR and FT-Raman spectra of the compound have been recorded and compared to the calculated frequency values. The total energy distribution of the fundamental modes has been obtained using scaled quantum mechanical program. The 1H NMR chemical shifts have been calculated using the gauge-independent atomic orbital approach. The theoretical electronic absorption spectra have been calculated using time-dependent density functional theory. The conductor-like screening solvation model has been applied to calculate the chemical shifts and maximum absorption wavelength values. The calculated values have been compared with the corresponding experimental results. © 2012 Wiley Periodicals, Inc.