Single‐Atomic Pd Embedded 2D g‐C3N4 Homogeneous Catalyst Analogues for Efficient LMCT Induced Full‐Visible‐Light Photocatalytic Suzuki Coupling**

Abstract We report the implementation of the ligand‐to‐metal charge transfer (LMCT) in organic semiconductors for improved full visible‐light photocatalysis and understanding of the effects of Pd−N weak coordination of a single‐atomic Pd(II) embedded 2D g‐C 3 N 4 (Pd 1 /UTCN) homogeneous catalyst analogues on the formation of open metal sites and LMCT induced full‐visible‐light photocatalytic performance. LMCT between Pd(II) and g‐C 3 N 4 allows for wide‐range visible light harvesting and promoting the transport of photogenerated charge of carbon nitride from excitation site to active site. Compared to the porphyrin palladium complex with strong Pd−N coordination, the reversible coordination dissociation of Pd−N of Pd 1 /UTCN allows for the formation of open active sites photocatalysis, which enables the efficient adsorption, activation, and conversion of substrates. The adsorption of the substrate can promote LMCT between Pd(II) and heptanazine ligands. As a result, Pd 1 /UTCN exhibited LMCT‐induced efficient full‐visible‐light photocatalytic activity of Suzuki reaction with high selectivity without additional phosphorus ligands.