The object of the invention covers the halogen derivatives of benzo[b]furans represented by formulas 1a and 1d : , as well as the use of the group of halogen derivatives of benzo[b]furans represented by the general formula 1 : wherein: R 1 , R 2 , R 3 , R 4 , R 5 , R 6 are such combinations of substituents which make the structure of the compound have at least one halogen atom, for the production of anti-neoplastic drugs and/or anti-proliferative drugs (e.g. leukaemia).