1-Bromo-4-ethylbenzene is primarily used as an intermediate in organic synthesis. It plays a key role in the production of various pharmaceuticals, agrochemicals, and specialty chemicals. The compound is often utilized in cross-coupling reactions, such as Suzuki or Heck reactions, to create complex organic molecules. Additionally, it serves as a building block in the synthesis of liquid crystals, which are essential components in display technologies like LCDs. Its bromine atom makes it a valuable reagent for introducing the ethylbenzene moiety into larger molecular structures.