This book highlighted the methods used for the syntheses of oxazolone compounds and their biological importance. The activity of oxazolones and their synthetic importance were investigated. It also reported a good introduction for the literature survey of lube oil additives including detergents dispersants additives and viscosity index improvers. In this context, we reported herein the behavior of oxazolone derivative towards some active reagents as a facile and convenient route to some heterocyclic derivatives containing oxazolone or imidazolone moieties. The methods of synthesis and the synthetic mechanisms of the aforementioned reactions were well presented. This book evaluated the synthesized compounds as antioxidant additives for lube oil and corrosion inhibitors for Fe, Cu and Al metals. The investigated compounds exhibited excellent antimicrobial activities against Gram positive, Gram negative and Fungi strains and have a direct antimicrobial effect on it.