2,3,4'-Trichlorobiphenyl is a polychlorinated biphenyl (PCB) congener historically used in industrial applications, such as a component in dielectric fluids for transformers and capacitors due to its stability and insulating properties. It was also utilized in heat transfer systems and as a hydraulic fluid in specialized machinery. However, due to its persistence in the environment, bioaccumulation, and toxicity, PCBs have been banned or severely restricted globally since the late 20th century. Today, it is primarily employed in research settings to study the environmental fate, degradation, and remediation of chlorinated biphenyls, as well as serving as an analytical standard for detecting PCB contamination in soil, water, air, and biota.