The primary objective of this present work is to develop synthetic procedures for the construction of biologically important nitrogen heterocycles such as quinazoline, benzimidazole, beta-carboline, benzothiazole by employing different oxidant in a sustainable way. The first chapter describes N-bromosuccinimide promoted synthesis of beta-carbolines and 3,4-dihydro-beta-carbolines from tetrahydro-beta-carbolines. The second chapter of this thesis involves o-iodoxybenzoic acid mediated tandem synthesis of quinazolines and dihydroquinazolines from 2-aminobenzylamine. Chapter-3 involves an oxone mediated tandem synthesis of benzimidazoles via a ring distortion strategy. The last chapter describes anhydrous cerium chloride catalyzed, 2-iodoxybenzoic acid mediated oxidative dehydrogenation of multiple heterocycles at room temperature.