When colloidal nanocrystals assemble into superlattices with long-range order, the super-sized crystals often have interesting electronic, optical and magnetic properties. However, the weak non-covalent forces holding the nanocrystals together make the superlattices fragile to solvents, heat and other stimuli, limiting their use in applications. Now writing in ACS Nano, Hao Zhang and colleagues introduce a general strategy to stabilize all flavours of 2D and 3D nanocrystal superlattices.