Zn(H

Birefringent crystals can modulate and detect the polarization of light, and have been widely used in the field of optoelectronic devices. The combination of a d10 transition metal cation and π-conjugated (H2C3N3O3)- group is a feasible approach for the synthesis of new crystal structures possessing large birefringence and short cutoff edges. Herein, a new hydroisocyanurate birefringent material Zn(H2C3N3O3)2·3H2O (ZHCY) was synthesized by a mild hydrothermal method. ZHCY featured a 2D layered ribbon structure constituted by coplanar π-conjugated (H2C3N3O3)- hydroisocyanurates, and displayed a wide band gap (5.24 eV) and a large birefringence (Δnexp ∼ 0.323, Δncal = 0.283 at 800 nm). Theoretical calculations revealed that its optical properties mainly originated from the π-conjugate coplanar (H2C3N3O3)- groups, which contribute to the enhancement of birefringence.