1-Bromo-4-chlorobutane (CAS No. 6940-78-9) is a halogenated organic compound used as a key intermediate in organic synthesis. It consists of a four-carbon alkane chain with bromine (-Br) and chlorine (-Cl) atoms at opposite ends, making it highly reactive in nucleophilic substitution and coupling reactions. It is widely used in pharmaceuticals, agrochemicals, and material sciences for synthesizing complex molecules.