Biphenyl-4,4'-diacetic acid is primarily utilized in the field of organic synthesis and material science. It serves as a key intermediate in the production of liquid crystals, which are essential components in displays for electronic devices such as LCD screens. The compound's rigid biphenyl core and flexible acetic acid groups make it suitable for creating stable and ordered molecular structures. Additionally, it is employed in the development of pharmaceuticals, where it acts as a building block for synthesizing active pharmaceutical ingredients (APIs) with specific biological activities. Its role in polymer chemistry is also notable, as it contributes to the creation of high-performance polymers with enhanced thermal and mechanical properties.