a b s t r a c t 4,4 -Dimethyl-2,2 -bipyridine is a useful but expensive chelating agent. Having more efficient routes to the synthesis of this compound would be advantageous to the wide-spread use of this fine chemical. In this work, the effects of adding strongly interacting oxides (ZnO, CeO 2 , and ZrO 2 ) to PdO catalysts supported on high surface area n-Al 2 O 3 (+), n-MgO, and n-TiO 2 prepared via co-and sequential precipitation were investigated. The product yields obtained from these catalysts in the oxidative coupling of 4-methylpyridine are dependent on the additive, the support, and preparation method. Evidently, these are complex catalytic systems in that the PdO-additive and PdO-support interactions must be right to promote product formation while preventing palladium leaching and support or additive migration over the active Pd/PdO sites. Although PdO/n-ZnO catalysts are reasonably active in the coupling reaction, ZnO addition to PdO catalysts supported on n-Al 2 O 3 (+), n-MgO, or n-TiO 2 does not increase the yield in any case. CeO 2 and ZrO 2 can increase the product yields in the reaction depending on the support used. Due to strong PdO-CeO 2 interactions, the addition of CeO 2 in some cases results in CeO x -migration and coverage of active PdO species or disrupts favorable PdO-support interactions leading to Pd leaching. Therefore, ZrO 2 is the better additive with co-precipitated PdO/ZrO 2 /n-Al 2 O 3 (+) consistently producing yields in excess of 3.4 Β± 0.1 g/g catalyst which is 36% higher than the 2.5 Β± 0.16 g/g catalyst obtained from the PdO/n-Al 2 O 3 (+) (5 wt% Pd), the best catalyst previously reported for this reaction.