A series of highly luminescent [Pt(NˆCˆCˆN)] emitters (ZPt1, ZPt2 and ZPt3) based on pyrazolo[1,5-f]phenanthridine-containing ligands were designed and synthesized. These Pt(II) complexes demonstrated extremely high thermal stabilities with the 5% weight-reduction temperatures over 450 °C due to the incorporation of the rigid pyrazolo[1,5-f]phenanthridine motif and the robustness of the tetradentate coordination framework. These Pt(II) complexes have the same coordination set (pyridineˆbenzeneˆbenzeneˆpyrazole) but with slightly different linkage between coordination groups. Within ZPt1 and ZPt2, pyridine and the neighboring benzene groups are separated by oxygen and aniline, respectively. In ZPt3, pyridine group is rigidly grafted on the carbazole unit. The effect of the different linkages on the frontier orbital energies, the photophysical and electroluminescent properties of ZPt1-ZPt3 was investigated systematically. Organic light emitting diodes (OLEDs) based on these Pt(II) complexes were fabricated with typical device structure. The Pt(II) complexes displayed intense electroluminescence in the blue to yellowish green spectral region. Among the three Pt(II) complexes, the 3-(pyridin-2-yloxy)phenoxy-based ZPt1 compound showed the highest electroluminescence performance with the maximum CE, PE, and EQE of 58.0 cd A⁻¹, 51.6 lm W⁻¹, and 16.4%, respectively.