Recent inve-stigations have shown that coupling luminescence with dendrimer chemistry can lead to systems capable of exhibiting quite unusual and interesting properties. In this trend article we focus on: (i) interactions of luminescent units within a dendrimer, (ii) quenching of dendrimer luminescence by external species, (iii) sensitization of luminescent metal ions, and (iv) sensitization and quenching of dye luminescence. Several examples of dendrimers are discussed, including compounds capable of: (a) performing excimer and/or exciplex emission, (b) exploiting energy transfer for harvesting light, (c) undergoing electron transfer processes, (d) protecting with their branches the luminescence of the core, (e) down and up converting light frequency, (f) playing the role of ligands for luminescent and non-luminescent metal ions, and (g) performing as hosts for luminescent dyes.