Phenylpyridine ligands are aromatic heterocyclic compounds containing pyridine and benzene rings, which provide multiple coordination sites for metal ions. These ligands can form metal complexes with various metals, including ruthenium, iridium, and platinum, and are known for their luminescent properties. Phenylpyridine-based metal complexes are widely used in organic light-emitting diodes (OLEDs) and luminescent sensors due to their high quantum yield and stability. They also have potential applications in catalysis and photocatalysis as ligands for metal catalysts to improve reaction efficiency and selectivity. In addition, phenylpyridine ligands are used to synthesize coordination polymers and functional materials with unique properties.