Treatment of trans-[PtCl2(NCR)(2)] [R = Et 1, nPr 2, tBu 3, CH2Ph 4, Ph 5, p-CF3C6H4 6, NMe2 7, NEt2 8, N(CH2)(5) 9] with 2.5 equiv. of 2,3-diphenylmaleimidine in CH2Cl2 at room temperature for 5 min [for R = p-CF3C6H4 6, NMe2 7, NEt2 8, N(CH2)(5) 9] or 14 h (for R = Et 1, nPr 2, tBu 3, CH2Ph 4, Ph 5) furnishes (1,3,5,7,9-pentaazanona-1,3,6,8-tetraenato) platinum(II) [(PANT) Pt-II; PtCl{HN= C(R)N= CN[C(Ph)= C(Ph)] C= NC(R)= NH}] complexes 10-18. These species are formed by platinum(II)-mediated double coupling of 2,3-diphenylmaleimidine with both nitrile ligands. The formulation of the complexes was supported by satisfactory C, H, and N elemental analyses, which were in agreement with HRESI-MS, IR, and H-1 and C-13{H-1} NMR spectra. The structures of 10, 11 center dot 1/8nC(6)H(14), 15, 16 center dot CCl4, and 17 center dot CHCl3 were determined by single-crystal X-ray diffraction. Absorption and emission studies were performed on representative complexes 10, 15, and 18, and the results show weak phosphoresce