Binuclear Pd­(II) and Pt­(II) complexes supported by rac-dpmppm (bis­[(diphenylphosphinomethyl)­phenylphosphino]­methane) in a triply-bridged Z-form, [M2Cl4(rac-dpmppm)] (M = Pd (3a), Pt (3b)), readily reacted with 2,6-xylyl isocyanide (XylNC) in the presence of NH4PF6 to afford [M2Cl2(rac-dpmppm)­(XylNC)2]­(PF6)2 (M = Pd (4a), Pt (4b)), in which each metal center accommodates one isocyanide ligand at the trans position to the inner P atom of dpmppm. Similarly, treatment of 3a and 3b with axially chiral (R/S)-1,1′-binaphthyl-2,2′-bisisocyanide (rac-Binac) in the presence of NH4OTf gave cyclic tetranuclear complexes, [{M2Cl2(rac-dpmppm)­(rac-Binac)}2]­(OTf)4 (M = Pd (5), Pt (8)), where two {M2Cl2(rac-dpmppm)}2+ fragments are connected by two rac-Binac ligands through chirality sorting of (R*,R*)-dpmppm and (R*)-Binac. Complex 5 could be transformed into the halide exchanged tetranuclear complexes, [{Pd2X2(rac-dpmppm)­(rac-Binac)}2]­(OTf)4 (X = Br (6), I (7)), to show that the rectangular arrangement of four Pd­(II) ions is elongated by repulsive interaction between halide ligands. By using (R)- and (S)-Binac, enantiopure Pd4 complexes, [{Pd2Cl2((R*,R*)-dpmppm)­((R*)-Binac)}2]­(OTf)4 (5 RR/R and 5 SS/S ), were successfully isolated as pure crystalline forms, from which enantiopure (R,R)- and (S,S)-dpmppm were obtained by treatment with NaCN aqueous solution. Namely, optical resolution of rac-dpmppm was established through the tetranuclear Pd complexes, which is the first example for methylene-bridged polyphosphines, R2P­(CH2PR) n CH2PR2 (n > 0). Furthermore, chiral octapalladium chains, [Pd8((R*,R*)-dpmppm)4­(NCCH3)2]­(BF4)4 (2 RR and 2 SS ), were synthesized by reacting enantiopure P-chiral dpmppm with [Pd2(CH3CN)6]­(BF4)2 and [Pd2(dba)3]·C6H6 and were characterized by spectroscopic and X-ray crystallographic analyses, to determine the absolute configurational structures. The Pd8 chains are the longest enantiopure chiral single-metal-atom chains structurally characterized, thus far, and the electronic structures were examined on the basis of DFT calculations of 2 RR .