Four novel IrIII and PtII complexes with cyclometalated ligands bearing a carbazole framework are prepared and characterized by elemental analysis, NMR spectroscopy, and mass spectrometry. Single‐crystal X‐ray diffraction studies of complexes 1, 3, and 4 reveal that the 3‐ or 2‐position C atom of the carbazole unit coordinates to the metal center. The difference in the ligation position results in significant shifts in the emission spectra with the changes in wavelength being 84 nm for the Ir complexes and 63 nm for the Pt complexes. The electrochemical behavior and photophysical properties of the complexes are investigated, and correlate well with the results of density functional theory (DFT) calculations. Electroluminescent devices with a configuration of ITO/NPB/CBP:dopant/BCP/AlQ3/LiF/Al can attain very high efficiencies. Carbazole‐based metal complexes exhibiting emission from blue‐green to red have been designed and prepared. Their energy levels, photoluminescence, and electroluminescence are tuned by controlling the ligation of the metal (IrIII or PtII) with the carbon atom at the 2 or 3 position of the carbazole unit. Highly efficient OLED devices using the complexes as phosphorescent dopants have been achieved (see figure).