Treatment of tetranuclear palladacycles with 2-(diphenylphosphino)pyridine, Ph2Ppy, in acetone at room temperature for 10 h, gave the new bidentate [N,S] palladacycle metalloligands 1-7. Treatment of [Rh 2Cl2(CO)4] with AgClO4 in acetone at room temperature for 10 min, followed by addition of 1-7 and stirring at room temperature for 10 h, gave the novel heterobimetallic palladium-rhodium compounds 1a-7a as 1:1 electrolytes, where the new bidentate [N,S] palladacycle metalloligands are bonded to the second metal through the pyridine nitrogen atom, and the sulfur atom of the thiosemicarbazone moiety; they exhibit a six-membered bimetallic central ring of differing atoms. In a similar manner, reaction of [PdBr2(Ph2PR4PPh2)] (R4 = CH2, C=CH2, (CH2)2, cis-CH=CH) with AgClO4 in acetone at room temperature, followed by addition of 1-7, gave the homobimetallic palladium-palladium compounds, 2b, 3b, 5b-7b, and 5c-7c, as 1:2 electrolytes, also with [N,S] coordination of the corresponding metalloligand. 1H-15N HMBC experiments were a most valuable tool in helping to unequivocally ascertain rhodium-nitrogen and palladium-nitrogen coordination in the bimetallic species. The crystal and molecular structures of 3, 6, 2b, and 3b have been determined by X-ray crystallography; for compounds 3 and 3b, inter- and intramolecular interactions in the solid state result in crystal self-organization, leading to chains and/or layers in the molecular array. © 2014 American Chemical Society.