Based on this structure, one of the acetoxy anions of Pd(OAc)2 was replaced with L1 to make a palladium acetoxy phenoxide. The distance between two palladium cations is 6.907 Å, which is suitable for binding malononitrile (or a generated anion of malononitrile), and there is one H2O molecule positioned at the center of the asymmetric sphere. L1-Pd2 reacted smoothly with malononitrile. The 1H NMR spectrum of free malononitrile in CDCl3 shows a single methylene peak at 3.60 ppm. When malononitrile is added to 1 equiv. of L1-Pd2, the peak was shifted to 2.43 ppm 1H NMR (see details in Supplementary Information). ESI-MS analysis of a 1:1 mixture of malononitrile with L1-Pd2 showed a clear new peak at m/z = 1123.1764, attributed to [L1(−2H) + Pd2 + NCCHCN]+.