In this study, ten novel disazo dyes based on aminothiazoles (4a-e, 5a-e) were synthesized in the first section. By using their 1H-NMR, FT-IR, and UV-Vis spectra, these synthesized dyes’ structures were verified. In the second section, the density functional theory (DFT) was used to calculate the molecular geometry, vibrational frequency and molecular electrostatic potential (MEP) diagram in the ground state using the B3LYP level and the 6-311 G(d,p) basis set. UV-vis data were obtained using the Gaussian 09 TD-DFT Cam-B3LYP 6-311 G ++ (d,p) basis set. To explore the chemical shift values, the gauge independent atomic orbital (GIAO) approach was used. Time-dependent DFT (TD-DFT) approach was used to determine the HOMO–LUMO calculations. As a consequence of our research, it was found that the experimental values and the computational spectroscopic values of the synthesized disazo compounds were consistent.