Abstract A series of dichlorodiimine complexes [M (NN) Cl 2] z of Au (III) and Pt (II) with 1, 4- derivatives of o-phenanthroline [(NN)= o-phenanthroline (phen), dipyrido [f, h] quinoxaline (dpq), dipyrido [a, c] phenazine (dppz), 6, 7-dicyanodipyrido [f, h] quinoxaline (dicnq)] were prepared and characterized by 1 H NMR, electronic absorption, and emission spectroscopy and by cyclic voltammetry. In all the complexes, the 3 (π-π*)-type transition is the spin- ...