Hydrazine monohydrobromide is primarily used as a reducing agent in various chemical reactions. It is effective in organic synthesis for the reduction of nitro compounds to amines, which is a critical step in the production of dyes, pharmaceuticals, and agrochemicals. Additionally, it serves as a precursor in the synthesis of other hydrazine derivatives, which are valuable intermediates in the manufacture of polymers and plastics. In the field of analytical chemistry, it is utilized for the determination of certain metals and organic compounds due to its strong reducing properties. Its application also extends to the preparation of blowing agents for foams and as a component in rocket propellants, where it acts as a fuel source.