Phenylmethanesulfonohydrazide is primarily used as a blowing agent in the production of foamed plastics. It generates nitrogen gas upon decomposition, which helps create a uniform cellular structure in materials like polyvinyl chloride (PVC), polyethylene, and rubber. This makes it valuable in manufacturing lightweight, insulating, and cushioning products such as foam sheets, gaskets, and seals. Additionally, it is employed in the synthesis of pharmaceuticals and agrochemicals, where it acts as an intermediate in the preparation of various active compounds. Its controlled decomposition properties also make it suitable for applications in the textile industry, particularly in creating foamed coatings or finishes.