[Zn(C7H3O5N)]n · nH2O: A third-order NLO Zn coordination polymer with spiroconjugated structure

[Zn(C7H3O5N)]n · nH2O, possessing an anticlockwise windmill-like framework structure and formating spiroconjugation, which is predicted to have large third-order polarizability, showed strong third-order NLO absorptive properties, and its n2 value was calculated to be 4.15 × 10−11 esu.