This book reviews the fundamental aspects of quinoxaline chemistry: synthesis, reactions, mechanisms, structure, properties, and applications. The first five chapters present a survey the developments in quinoxaline chemistry since the publication of the monograph on "Condensed Pyrazines" by Cheeseman and Cookson in 1979. These chapters give a comprehensive coverage of the important quinoxaline-containing ring systems such as thiazolo[3,4-a]-, pyrrolo[1,2-a]-, imidazo[1,5-a]quinoxalines, etc. The remaining sixth chapter gives a review of all the previously known rearrangements of heterocyclic systems that lead to benzimidazole derivatives. A critical analysis of these transformations reveals novel acid-catalyzed rearrangements of quinoxalinones giving 2-heteroarylbenzimidazoles and 1-heteroarylbenzimidazolones in the presence of nucleophilic reactants. Existing literature is thoroughly and critically reviewed.