Modulating Magnetoelectric Dipole by Salt‐Bridge Hydrogen Bonds Assembly to Amplify Circularly Polarized Luminescence

Lanthanide ions are promising for high‐performance circularly polarized luminescence (CPL) materials due to the significant transition magnetoelectric dipole properties. Consequently, controlling the magnetoelectric dipole moments is a key for enhancing their CPL performance. Here, we assembled a chiral europium assembly (Eu 2 assembly) from an Eu(III) complex, which manipulated the structure of complex monomer and modulated the orientation and magnitude of the magnetoelectric dipole moments, leading to a dramatic enhancement in CPL performance. The resulting material exhibits a high quantum yield of 42% (up from 27%) and a luminescence dissymmetry factor of 0.106 and 0.0857, representing a 10‐fold enhancement over the precursor complex (0.0113 and 0.00907). This work not only establishes a clear structure–dipole–performance relationship but also provides a general strategy for developing high‐performance lanthanide‐based CPL materials.