A novel naphthalenediimide-based lanthanide-organic framework with polyoxometalate templates exhibiting reversible photochromism.

The first visible-light-responsive photochromic polyoxometalate-templated lanthanide-organic framework (LOF) has been constructed from a carboxyphenyl-substituted naphthalenediimide (NDI) derivative, which displays an unusual four-fold interpenetration of an srs topological network, featuring a variety of anion-π interactions between polyoxoanions and π-acidic NDI moieties, and undergoes a rapid reversible photochromic transformation upon blue light irradiation.