Mixed Coordination and Pronounced Distortion Enabling Strong Nonlinear Optics in Chiral Lead Halides

ABSTRACT Chiral hybrid metal halides are regarded as promising candidates for next‐generation second‐harmonic generation (SHG) applications owing to their inherent non‐centrosymmetry. However, the SHG responses in chiral materials featuring complex mixed‐coordinate (MC) inorganic architectures remain largely unexplored. Herein, we report a novel class of coordination‐engineered chiral MC lead halides, R/S ‐DAP 2 Pb 5 Cl 14 ·H 2 O ( R/S ‐DPC), assembled using chiral organic spacers. Single‐crystal X‐ray diffraction reveals that R/S ‐DPC crystallizes in the chiral space group C 2, featuring unique inorganic chains with MC Pb centers. The significant lattice distortion induced by coordination engineering simultaneously enables broadband green emission (400–700 nm) and robust SHG activity. Notably, R/S ‐DPC exhibits a strong SHG response across an ultrabroadband wavelength range (800–3200 nm), with an intensity approximately 10.6 times that of KH 2 PO 4 (KDP). Furthermore, an exceptional SHG dissymmetry factor ( g SHG‐CD ) of 0.97 is achieved, placing R/S ‐DPC among the most efficient chiral MC lead halides reported to date. Moreover, strategic Cu 2+ doping extends the spectral response for self‐powered photodetection, while well preserving the intrinsic chirality and nonlinear optical activity of the mixed‐coordinate framework. This work validates coordination engineering as a powerful strategy for designing multifunctional chiral materials that synergistically integrate structural complexity and high SHG performance.