Acyclic phosphazenes or iminophosphoranes continue to be of interest because of at least three reasons, One, they are good ligands for binding to transition metal ions as well as lanthanide (and some actinide) metal ions. Two, they can be extremely strong bases. Lastly, many of these compounds find applications either in the form of their metal complexes or as free ligands in a multitude of catalytic reactions ranging from various polymerization reactions to asymmetric synthesis. This section deals with different types of acyclic phosphazenes including the assembly of some new acyclic phosphazenes.^1–37

Benzo-1,2,3-thiazaphosphole (1) was synthesized by...