This study describes the new simple and accurate spectrophotometric method for the determination of paracetamol after the formation of azo dye with a new chromogenic reagent 4 [(2-amino-1,3thiazol-4-yl)amino] nitrobenzene to form an orange-coloured product measured at 425 nm. The molecular structure of the newly synthesized compound was confirmed by several spectroscopic techniques such as UV-visible, FTIR, 1HNMR, and mass spectroscopy. Newly synthesized compound was in vitro screened against several bacterial species. The experimental conditions that affect the reaction were carefully optimized and under the optimized conditions, a linear relationship was obtained in the concentration range of 5–25mg.L−1 of paracetamol. A reaction with a new chromogenic reagent has been occurred at a stoichiometric ratio of 1:1. This method has a limit of detection of 1.334 mg.L-1 and Sandell's sensitivity of 0.0235 mg.cm-1 for new azo dye product.