Coumarins are the most important oxygenated heterocyclic of natural compounds. They are widely used as raw materials in many areas such as agrochemical, perfume, pharmaceutical industries. They therefore have several physical, chemical and biological properties. In order to enlarge this family of compounds and elucidate almost all of its properties, researchers have developed various synthetic methods that are not very complex and less expensive. Thus, from 4-hydroxycoumarin we have synthesized a series of 3-acyl-4-hydroxycoumarins by C-acylation. This study is therefore dedicated to the reactivity of 3-acyl-4-hydroxycoumarins. The synthesized coumarins showed a high reaction potential based on the chemical functions present in their structures. To enhance them later, we can try to graft other functions which can be the subject of several transformations such as: condensation, functionalization, cyclization, acylation. So to access more interesting new poly-functionalized compounds both at the reactivity and biological level. These molecules (3-acyl-4-hydroxycoumarins) being new, very little information is known on their physicochemical behavior in writings. On the other hand, the reactivity of molecules with similar structures to those of acyl-hydroxycoumarins such as 4-acylisochroman-1,3-diones and 3-acetyl-4-hydroxycoumarin have been the subject of scientists' work. It emerges from this study that 3-acyl-4-hydroxycoumarins shows strong chemical reactivity which can be used biologically.