Mesocrystals are 3D ordered nanoparticle superstructures, often with internal porosity, which receive much recent research interest. While more and more mesocrystal systems are found in biomineralization or synthesized, their potential as material still needs to be explored. It needs to be revealed, which new chemical and physical properties arise from the mesocrystal structure, or how they change by the ordered aggregation of nanoparticles to fully exploit the promising potential of mesocrystals. Also, the mechanisms for mesocrystal synthesis need to be explored to adapt it to a wide class of materials. The last three years have seen remarkable progress, which is summarized here. Also potential future directions of this reaserch field are discussed. This shows the importance of mesocrystals not only for the field of materials research and allows the appliction of mesocrystals in advanced materials synthesis or property improvement of existing materials. It also outlines attractive research directions in this field.