Chiral Supramolecular Templating Enables Tunable Second‐Harmonic Generation in Hybrid Zinc Thiocyanates

Chiral organic molecules have been widely used to construct hybrid nonlinear optical (NLO) materials with second‐harmonic generation (SHG) activity. However, the limited diversity of chiral building blocks has restricted both structural diversity and SHG performance. Herein, we introduce a chiral supramolecular templating strategy for engineering hybrid zinc thiocyanates with tunable SHG responses. Alkali or alkaline‐earth metal ions and natural amino acids cooperatively assemble into one‐dimensional (1D) chiral coordination polymers that serve as supramolecular templates, while the hard‐soft acid‐base principle suppresses undesired coordination between amino acid ligands and zinc ions. This coordination orthogonality enables different chiral supramolecular templates to direct the spatial organization of the SHG‐active [Zn(SCN) 4 ] 2− units. The resulting hybrid solids combine wide optical bandgaps, phase‐matchable birefringence, and diverse SHG responses. Notably, [K 2 (L‐ser)][Zn(SCN) 4 ] exhibits an SHG intensity of 8.0 × KH 2 PO 4 , representing the strongest response reported to date for homochiral zinc‐based materials derived from natural amino acids. Theoretical analyses reveal that the [Zn(SCN) 4 ] 2− units dominate the SHG response, establishing chiral supramolecular templating as a general strategy for designing high‐performance hybrid NLO materials.