Monodispersed nanocrystals (NCs) can form ordered and functional binary superlattices. A variety of functional binary nanocrystal superlattices (BNSLs) and bilayer assemblies based on lanthanide-doped NaREF4 (RE = Y, Gd) were constructed with different assembly methods. These assemblies are attractive for applications in photonics as they display multicolor upconversion (UC) emissions.