We designed two near-infrared (NIR) lanthanide complexes [(L) 2 -Nd(NO 3 ) 3 ] (L = TPE 2 -BPY for 1, TPE-BPY for 2) by employing aggregation-induced emission (AIE)-active tetraphenylethylene (TPE) derivatives as sensitizers, which possessed matched energy to Nd III , prevented competitive deactivation under aggregation, even shifted the excitation window toward 600 nm by twisted intramolecular charge transfer. Furthermore, benefiting from the 4 f electron shielding effect and antenna effect, the enhanced excitation energies of the AIE-active sensitizers by structural rigid-ification transferred into the inert Nd III excited state through 3 LMCT, affording the first aggregation-induced phosphorescence enhancement (AIPE)-active discrete NIR-emitting lanthanide complexes. As 1 equipped with more AIE-active TPE than 2, L!Nd energy transfer efficiency in the former was higher than that in the latter under the same conditions. Consequently, the crystal of 1 exhibited one of the longest lifetimes (9.69 μs) among Nd III -based complexes containing CÀ H bonds.

Attaching AIE-active L1 ([1,1':2',1'':4'',1'''-quaterphenyl]-2-yldiphenylphosphane) to AuCl, shortened the distances of PÀ C bonds to promote electron cloud overlap between Au I and L1, affords 1 (L1AuCl) with aggregationinduced phosphorescence enhancement (AIPE) activity by 3 LMCT transitions. Then substituting the coplanar L2 (9ethynylanthracene) for the Cl À in 1 providing 2, switches the luminescence to aggregation-caused quenching (ACQ) activity. Furthermore, we restore the performance from ACQ to AIPE by metathesis reactions to transfer 2 into 1. It is versatile synthetic strategy of reversible transformation between 1 and 2 that switches the luminescence of organogold(I) between AIPE and ACQ through balancing auxiliary ligands around the given metal.