Disclosed is an electroluminescent device comprising a light-emitting layer containing a light emitting material that contains an organometallic complex comprising a metal selected from the group consisting of Pt, Pd and Ir, and a tridentate (N^C^N) ligand, wherein the tridentate (N^C^N) ligand represents a ligand that coordinates to the metal through a nitrogen donor bond, a carbon-metal bond, and a nitrogen donor bond, in that order, wherein at least one of the nitrogen donors is part of an aromatic ring or an imine group. The invention also includes a display or room lighting device employing the device of the invention and a process of emitting light from the device of the invention. The device of the invention provides good luminance efficiency.