Heterocyclic compounds especially pyrazolo[1,5-a]pyrimidines and 1,2,4-triazines exhibited various biological and pharmacological applications such as DNA binding, anti-tubercular, antiviral, anti-inflammatory, antioxidant, antimicrobial and anticancer. Therefore, the main objective of this book is to display the synthesis, spectral analysis and biological evaluations of some pyrazolo[1,5-a]pyrimidines and 1,2,4-triazines.