Abstract: Cancer is at present one of the most leading causes of death in the developed countries, and many efforts have been made to discover agents endowed with cytotoxic action. Natural products, with their ability to interact with more than one target, represent in medicinal chemistry a significant source of inspiration for the design of structural analogues with an improved pharmacological profile. Coumarins are an important family of natural and synthetic origin that has been attracting an intense interest in recent years for their remarkable array of biological activities, usually associated to low toxicity. It has been shown that 4-hydroxycoumarins derivatives bearing an aryl group in the 3 position of the coumarin skeleton, inhibit cell proliferation. Furthermore, a recent study shows that the most simple 4-hydroxycoumarin leads to a selective cytoskeleton disorganization in melanoma cells without affecting a non-tumoral fibroblastic cell line. Taking into account previous data about anti-tumor effects of coumarin derivatives we synthesized a new series of compounds structurally related to these, but exhibiting a new pattern of substitution that does not occur in nature and is not present in previously tested compounds. In particular in this communications we investigated the impact of different substituents at C-6 and the introduction of a hydroxyl group in diverse positions on the 3-aryl ring of the 4-hydroxycoumarin moiety on their antiproliferative activity by using two cancer cell lines.