Benzaldehyde p-toluenesulfonylhydrazone is a key reagent and intermediate in organic synthesis, particularly in the Shapiro reaction for regioselective formation of alkenes via vinyllithium intermediates and in the Bamford-Stevens reaction for generating diazoalkanes and carbenes. It is widely used in the preparation of heterocyclic compounds and other nitrogen-containing structures valuable for pharmaceuticals and agrochemicals. The compound facilitates studies of reaction mechanisms involving carbon-nitrogen bond formation/breaking and nitrogen extrusion. In analytical chemistry, it serves as a derivatization agent for detecting and quantifying carbonyl compounds.