Advances in Heterocyclic Chemistry, Volume 124, is the definitive series in the field—one of great importance to organic chemists, polymer chemists, and many biological scientists. Updates in this new volume include sections on the Organometallic Complexes of Azines, The Literature of Heterocyclic Chemistry, Part XV, Heterocycles Incorporating a Pentacoordinated, Hypervalent Phosphorus Atom, and Tautomerism and the Structure of Azoles: NMR Spectroscopy, amongst other related topics. Written by established authorities in the field, this comprehensive review combines descriptive synthetic chemistry and mechanistic insight to yield an understanding of how chemistry drives the preparation and useful properties of heterocyclic compounds.