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: R1, R2, R3, R4, R5, R6 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).