Ethyl 3-hydrazinylbenzoate hydrochloride is primarily utilized in organic synthesis as a key intermediate for the preparation of various heterocyclic compounds. It is often employed in the development of pharmaceuticals, particularly in the synthesis of hydrazide derivatives, which can exhibit significant biological activities such as antimicrobial, anti-inflammatory, and anticancer properties. Additionally, this compound is used in the production of dyes and pigments, where its hydrazine moiety plays a crucial role in forming complex structures with desired color properties. Its application extends to research laboratories, where it serves as a reagent for studying reaction mechanisms and developing novel chemical entities.