The Cu-I, Ag-I, and Au-I chemistry of a tetradentate ligand (phenylene-1,4-diaminotetra(phosphonite), p-C6H4[N{P(OC6H4OMe-o)(2)}(2)](2) (P2N Phi NP2) (1)) is described. The flexional conformations in 1 leads to interesting structural variations in transition-metal complexes. The reaction of 1 with 4 equiv of CuX (where X = Br and I) produce the tetranuclear complexes, [{Cu-2(mu-X)(2)(NCCH3)(2)}(2)(mu-P2N Phi NP2)] (where X = Br (2) or X = 1 (3)) in quantitative yield. Treatment of 3 with an excess of pyridine, 2-(piperazin-1-yl)pydmidine, and pyrazole yielded the tetra-substituted derivatives, [{Cu-2(mu-I)(2)(L)(2)}(2)(mu-P2N Phi NP2)1 (where L = pyridine (4), 2-(piperazin-1-yl)pydmidine (5), or pyrazole.(6)). Similar reactions of 3 with 1,10-phenanthroline (phen) and 2,2'-bipyridine in a 1:2 molar ratio afford the disubstituted derivatives, [(Cu-2(mu-I))(2)l(2)(phen)(2)(mu-P2N Phi NP2)] (7) and [(Cu-2(mu-I))(2)l(2)(bipy)(2)(mu-P2N Phi NP2)] (8). The o-methoxyphenoxy substituents on phosphorus in complexes 5 and 7 adopt approximately parallel planar conformations and contain lattice solvents. The reaction of 3 with 1,4-diazabicyclo[2.2.2]octane (DABCO) in a 1:2 molar ratio in a dichloromethane-acetonitrile mixture leads to the formation of an ionic complex [N(CH2CH2)(3)N+CH2Cl](2)[(Cu-2(Cl)(I)(2))(2)(NCCH3)(2)(mu-p2N Phi NP2)](2-) (9), as a result of the chloromethylation of DABCO. Treatment of 1 with 4 equiv of AgClO4 produces [{Ag-2(mu-ClO4)(2))(2)(C4H8O)(2)}(2)(mu-P2N Phi NP2)] (10). Displacement of perchlorate ions in 10 by PhN{P(OC6H4OMe-o)(2)}(2) (PNP) or 2,2'-bipyridine yielded [(mu-PNP)(2)Ag-2(mu-P2N Phi NP2)Ag-2-(mu-PNP)(2)](ClO4)(4) (11) and [{Ah(2)(bipy)(2)}(2)(mu-P2N Phi NP2)](ClO4)(4) (12), respectively. The similar reaction of 1 with 2 equiv of AgOTf, in the presence of 4,4'-bipyridine, gave a three-dimensional Ag-I coordination polymer, [{Ag-2(C10H8N2)(2) (CH3CN)(2)}(2)(P2N Phi NP2)](n)(OTf)(4n) (13). The reactions of 1 with [AuCl(SMe2)], in appropriate ratios, afford the tetranuclear and dinuclear complexes, [(Au2Cl2)(2)(mu-P2N Phi NP2)] (14) and [(AuCl)(2)(P2N Phi NP2)] (15). Complex 14 undergoes moisture-assisted P-N bond cleavage in the presence of PhN{P(OC6H4OMe-o)(2))(2) to give [p-NH2C6H4N(P(OC6H4OMe-o)(2)}(2)Au2Cl2] (17) and [PhN{P(OC6H4OMe-o)(2)}(2)Au2Cl2]. The strucures of the complexes 5, 7-10, 12-15, and 17 are confirmed by single-crystal X-ray diffraction studies.