5,2',3',6'-Tetrachlorobiphenyl-2-carboxaldehyde is a chlorinated biphenyl derivative featuring a formyl functional group at the 2-position and chlorine substituents at the 5, 2', 3', and 6' positions. This compound is primarily utilized as an intermediate in organic synthesis, particularly in the preparation of polychlorinated biphenyl (PCB) analogs for research applications. Its well-defined structure and high purity make it suitable for studies involving environmental analysis, toxicology, and degradation pathways of PCBs. The presence of multiple chlorine atoms enhances its stability, while the aldehyde group provides a reactive site for further functionalization. Careful handling is required due to its potential environmental persistence and toxicity.