Researchers have made a significant advance in the way they produce exotic open-framework superlattices made of hollow metal nanoparticles. The new method for preparing open-framework colloidal crystals leads to synthesis of 12 novel nanoparticle superlattices.Researchers have made a significant advance in the way they produce exotic open-framework superlattices made of hollow metal nanoparticles. The new method for preparing open-framework colloidal crystals leads to synthesis of 12 novel nanoparticle superlattices.