Amidines are the important classes of nitrogenous compounds, which have been widely used as antibiotics, diuretics, antiphogistic drugs, anthelmintics, and acaricides. They represent an important pharmacophore in modern drug discovery, and can be found in DNA and RNA binding diamidine diminazene, ASIC inhibitor, muscarinic agonists for the treatment of Alzheimer’s disease, platelet aggregation inhibitors, and recently, serine protease inhibitors, to give some examples. In fact, many of the top-selling pharmaceuticals of the fast few years feature an amidine as a key structural components. In addition, they also serve as ligands for transition metals due to their unique structure. These enormous significant applications have attracted the research community towards the development of simple and economically viable methods for the synthesis of amidines. Several synthetic methods have been developed, in which the nucleophilic addition of amine to nitrile is the most convenient and atom-economic method. In synthetic chemistry, amidines have been used as valuable precursors for the preparation of azaheterocycles of biological interest such as- imidazoles, benzimidazoles, quinazolines, triazine, triazoles, oxazole, pyrimidines, pyrimidopyrimidines etc. Recently, we have demonstrated a synthetic protocol for the preparation of substituted pyrimido[4,5-d]pyrimidines via TBHP-mediated direct oxidative coupling of N-uracil amidines and methylarenes under metal-free conditions. Very recently, we also reported the synthesis of functionalized pyrimidouracils by ruthenium catalyzed oxidative insertion of (hetero)aryl methanols into N-uracil amidines. A dehydrogenative coupling of N-uracil amidines with (hetero)aryl methanols has been developed, allowing for the facile synthesis of a broad range of structurally diverse pyrimidouracils. In this paper, recent advances in the synthesis of amidines and their application towards the preparation of biologically important heterocycles has been discussed.