5-Bromopyrimidine-2,4-diamine is primarily used in pharmaceutical research and development as a key intermediate in the synthesis of various biologically active compounds. It plays a significant role in the creation of antiviral and anticancer agents, particularly in the design of nucleoside analogs that target viral replication or cancer cell proliferation. Additionally, it is utilized in the development of kinase inhibitors, which are essential in regulating cellular signaling pathways and treating diseases like cancer and inflammatory disorders. Its structural properties make it a versatile building block in medicinal chemistry for designing molecules with specific therapeutic effects.