O-(4-Nitrophenyl)hydroxylamine is primarily used in organic synthesis as an intermediate for the preparation of various chemical compounds. It plays a significant role in the development of pharmaceuticals, particularly in the synthesis of active pharmaceutical ingredients (APIs) that require specific nitroaromatic structures. Additionally, it is utilized in the production of dyes and pigments, where its nitro group contributes to color formation and stability. In research, it serves as a reagent for studying reaction mechanisms, especially those involving nitroaromatic compounds and hydroxylamine derivatives. Its applications also extend to material science, where it is used in the modification of polymers and surfaces to introduce functional groups for further chemical reactions.