Abstract Ammoxidation of alkyl aromatics is a simple gas-phase reaction that yields aromatic nitriles. These nitriles, especially benzonitrile have versatile applications. This chapter project focuses on the ammoxidation of toluene: catalysts employed in industrial and lab-scale, significance and challenges, and mechanistic approaches; we have also tried to provide comparative studies of the mechanisms involved with the variable-valence transition metals (Mars-Van Krevelen mechanism) and confined single alkali metal ions within Y-zeolite pores involving acid-base catalysis.