What are the main uses of 4-Nitro-o-phenylenediamine (CAS: 99-56-9)?

4-Nitro-o-phenylenediamine (CAS: 99-56-9) is primarily used in the pharmaceutical industry as a precursor for dye intermediates and drug synthesis. It also finds applications in industrial chemistry for producing azo dyes and functional materials. In research, it serves as a building block for developing new compounds. Its versatility in chemical reactions makes it valuable across multiple fields, including organic synthesis and material science.