4-Chlorophenylhydrazinehydrochloride, abbreviated as 4-CPH, is a white to off-white crystalline solid. It is primarily utilized as a building block in organic synthesis, especially in the pharmaceutical industry. This compound is known for its ability to react with carbonyl compounds, making it valuable in the production of various pharmaceutical intermediates. Additionally, 4-Chlorophenylhydrazinehydrochloride is also employed in research settings for its role in studying organic reactions and as a reagent in chemical analysis.