An improved synthesis of polychlorinated biphenyls (PCBs) utilizing a palladium-catalyzed cross-coupling reaction (Suzuki-coupling) is described. The coupling of (chlorinated) aryl boronic acids 1–3 with bromochlorobenzenes 4 using the standard conditions of the Suzuki- coupling gave the desired PCB congeners 5–7 in good to excellent yields. The self-coupling product of the aryl boronic acids is the major impurity of this reaction. 3, 4, 5- ...