Lanthanide based tuning of luminescence in MOFs and dense frameworks--from mono- and multimetal systems to sensors and films. 
This feature article focuses on tuning options of photoluminescence properties of lanthanide containing Metal-Organic Frameworks (MOFs) and Dense Frameworks by selection of an appropriate set of metal ions together with suitable ligands.  In addition to lanthanide-only systems, frameworks with main group and transition metal ions that are heterometallic or co-doped with variable lanthanide content offer excellent tuning options for luminescence.  The MOF feature porosity enables further applications such as sensors for a large number of chemical analytes by selective influences on the luminescence upon contact.  The application of functional thin films marks the most recent development of this amazingly growing field, involving processing and structuring.