The invention relates to novel organic semiconducting (OSC) random copolymers containing a halo-substituted 4,8-dithiophenyl-benzodithiophene unit and a benzodithiophene-dione unit, to methods for their preparation and educts or intermediates used therein, to compositions and formulations containing them, to the use of the copolymers and compositions as organic semiconductors in, or for the preparation of, organic electronic (OE) devices, especially organic photovoltaic (OPV) devices, perovskite-based solar cell (PSC) devices, organic photodetectors (OPD), organic field effect transistors (OFET) and organic light emitting diodes (OLED), and to OE devices comprising these copolymers or compositions.