The current invention relates to novel platinum(II) based organometallic materials. These materials show high emission quantum efficiencies and low self-quenching constant. Also provided are high efficiency, green to orange emitting organic light-emitting diode (OLED) that are fabricated using platinum(II) based organometallic materials as the light-emitting material. The organometallic materials of the invention are soluble in common solvents; therefore, solution process methods such as spin coating and printing can be used for device fabrication. The devices fabricated from these materials show low efficiency roll-off.