1,4-Diphenylsemicarbazide is primarily used as a reagent in analytical chemistry for the detection and quantification of carbonyl compounds, such as aldehydes and ketones. It reacts with these compounds to form semicarbazones, which can be easily identified and measured, making it valuable in various chemical analyses. Additionally, it finds application in organic synthesis, where it serves as a building block for the preparation of more complex molecules, particularly in the development of pharmaceuticals and agrochemicals. Its role in polymer chemistry is also notable, as it can be used as a cross-linking agent or stabilizer in certain polymeric materials, enhancing their properties and performance.