This research work purposes to synthesize a novel derivative of 2-[1-(1,3-diphenyl-1H-pyrazol-4-yl)ethylidene]hydrazinyl)-4-methyl-5-phenyldiazinyl)thiazole (7), and then we measured and analyzed the optical properties of it as a thin film. The chemical structure of 2-[1-(1,3-diphenyl-1H-pyrazol-4-yl)ethylidene]hydrazinyl)-4-methyl-5-phenyldiazinyl)-thiazole (PT) was confirmed by the elemental analyses and spectroscopic techniques. Thin films of (PT) were achieved by the common vacuum thermal deposition system. A field emission scanning electron microscope (FESEM) was done to analyze the surface topology analysis of the newly prepared (PT) thin films. The optical spectroscopic analysis of (PT) was performed to obtain the optical absorption and emission transitions by different mathematical analytical methods. Some important optical parameters of (PT) thin film were predicted and compared with the experimental results by using DFT/TD-DFT calculations. The wide range absorption, emission, and suitable optical band gap prove an effective example of organic dye suitable for organic electronic applications.