The preparation and physical properties of the simple azo complexes trans-(RN═NR)2PdX2 (R = CH3, C6H6; X = Cl, Br) are reported. Infrared and nmr spectral observations indicate that each azo group is coordinated to palladium through a single nitrogen lone pair. Similar complexes of azoxybenzene could not be prepared, but it is possible to deprotonate azoxybenzene to form dichlorobis[2-(phenylazoxy)phenyl]dipalladium(II), 6. The dimer is readily cleaved by organic bases to give monomeric species. The preparation and properties of (C6H5NO)2PdCl2 are reported. © 1969, American Chemical Society. All rights reserved.