1-Phenylguanidine is primarily used in organic synthesis as a reagent for the preparation of various chemical compounds. It serves as a building block in the synthesis of pharmaceuticals, particularly in the development of drugs targeting cardiovascular diseases and hypertension. The compound is also utilized in the production of dyes and pigments, where it acts as an intermediate to enhance color properties. In research, it is employed as a tool to study enzyme inhibition, particularly in the context of nitric oxide synthase, which plays a role in regulating blood pressure and immune response. Additionally, 1-phenylguanidine finds application in the development of agrochemicals, contributing to the creation of pesticides and herbicides that improve crop yield and protection. Its versatility in chemical reactions makes it valuable in both industrial and academic settings.