Changing N^C^O to C^N^O Coordination in Cyclometalated Pt(II) and Pd(II) Complexes Modulates Stability and Emission Characteristics: Toward Brighter Versatility

In this work, we present a new class of cyclometalated Pt(II) complexes bearing tridentate luminophoric chelators. Inspired by picolinato units usually acting as ancillary ligands for phosphorescent Pt(II) and Ir(III) complexes with high‐lying triplet states, we herein incorporate this coordination pattern into chelating luminophores toward tridentate pincer ligands (C^N^O) and compared them with a benzoate‐derived motif (N^C^O). Both frameworks exhibit excellent photoluminescence efficiencies with quantum yields ( Φ L ) reaching up to 76% (N^C^O) and 75% (C^N^O). The versatile variation of the substitution patterns at the C^N^O motif was found to significantly affect the photophysical properties, yielding tunable emission maxima ranging from 475 to 693 nm. With the introduction of electron‐donating substituents, it was demonstrated that an electron‐rich cyclometalating ring at the luminophoric backbone enables the realization of Pd(II) complexes that are emissive in solution at room temperature, if combined with strong σ ‐donors (like N ‐heterocyclic carbenes) as co‐ligands. This comparative study demonstrates that both coordination patterns yield highly efficient emitters with excellent solubilities in common organic solvents. Notably, the C^N^O‐based motif offers distinct advantages for future applications, owing to its greater synthetic versatility and enhanced chemical accessibility.