The study of clusters of main group elements as ligands for transition metals has recently seen a renaissance, allowing for the extension of well-known classes of compounds into applications. These have shown structural and electronic advantages over classical organic ligand-coordinated transition metal complexes, with promising properties unique to the compound type. In this book chapter, we will cover advances in this field from the last decade. This will start with a review of typical synthetic methods and continue with a focus on structural dynamics, further reactivity, and catalysis.