Progress in Heterocyclic Chemistry (PHC), Volume 35 is the latest in this annual review series that contains both highlights of the previous year’s literature on heterocyclic chemistry and articles on new and developing topics of particular interest to heterocyclic chemists. Chapters in this new release are all written by leading researchers in their field, constituting a systematic survey of the important original material reported in the literature of heterocyclic chemistry in 2021. As with previous volumes in the series, this book will enable academic and industrial chemists, and advanced students, to keep abreast of developments in heterocyclic chemistry.