A new publication from the group Phonon-Mediated Nonradiative Relaxation in Ln3+-Doped Luminescent Nanocrystals tackles the unsatisfactory photoluminescence efficiency of Ln3+-doped nanocrystals that severely restricts their practical application. The publication shows that phonon-mediated nonradiative relaxation in Ln3+-doped nanocrystals is substantially influenced by a variety of factors. Moreover, without explicit knowledge and consideration of these factors, property analysis will probably end up with misinterpretation. Thus the use of knowledge established for bulk materials to interpret the experimental findings collected at the nanoscale should be cautiously scrutinized. The authors conclude that systematic studies are needed for the informed development of Ln3+-doped luminescent nanomaterials that can meet the application needs for a sustainable society.