Through a versatile synthesis of combretastatins we have prepared and assayed for activity some new compounds of this kind of antitumoral agents. Ketoderivatives (combretastatones) and other diphenylethane derivatives display low activity, but naphthylcombretastatin 3e shows activity comparable to that of the most potent combretastatins-B (dihydrocombretastatins), in spite of the lack of the 3-hydroxy-4-methoxyphenyl substructure considered to be neccesary for high antineoplastic potency.