This book is part of a program which deals with the design and synthesis of some new indole derivatives of pharmaceutical importance. The work aims to: (1) Explore and develop a new methodology for the synthesis of some novel heterocyclic compounds (pyrazolopyrimidine, pyrazole, imidazopyrazole, pyrazolodiazepine, pyrazolotriazine, and pyrazolothiadiazine) bearing an indole ring system. (2) Studying the reaction mechanism and elucidating the structure of these compounds by spectral data. (3) Studying the biological activity of these compounds as antioxidant agents using the ABTS method.