This book includes three chapters (from chapter III-V). Chapter I and II are already published under the title ¿An overview of indazoles and its synthetic intermediates¿.Chapter III describes the synthesis of pyrazolo and isoxazolo fused derivatives of 7,8,9-trihydropyrazolo[4,5-b]carbazol-6(3H)-one and 9-benzyl-7,8-dihydropyrazolo[4,5-b]azacarbazol 6(3H)-one. Chapter IV is concerned with the synthesis of pyrimidine ring incorporated derivatives of 7,8, 9-trihydropyrazolo[4,5-b]carbazol-6(3H)-one from oxo-ketenedithioacetals, chalcones, dimethylamino methylene ketones and enolic ethers of carbazole annulated pyrazoles. Chapter V is related with the synthesis of benzodiazepino, benzothiazepino and quinolino condensed 7,8,9-trihydropyrazolo[4,5 b]carbazol-6(3H)-one and 9-benzyl 7,8-dihydropyrazolo[4, 5-b]-9-azacarbazol-6(3H)-one from oxo-ketenedithioacetals and chalcones derived from carbazolo annulated pyrazole and azacarbazolo annulated carbazole.