This book presents an overview of the recent advancements for the synthesis of small- and medium-sized azaheterocycles, including pyrroles, indoles, pyrimidines, pyridines, pyrrolidines, imidazoles, pyrazoles, pyrazolines, lactams, and 1,2,3-triazoles, which are significant scaffolds for compounds with pharmaceutical uses. The book also discusses various properties and performance attributes of azaheterocycles including their bioactivity and synthetic strategies. Given the contents, the book will be a valuable reference for students, researchers, and professionals interested in organic synthesis and medicinal chemistry.