Novel compounds--substituted indolo[3,2-b]carbazoles (SIC)--which demonstrate semiconducting properties are synthesized. Electroluminescence (EL) is studied in multilayer diode structures based on SIC. The values of hole (6.38 x 10.sup.--5 cm.sup.2/(V s)) and electron mobilities (1.31 x 10.sup.--5 cm.sup.2/(V s)) of these electroactive materials are measured. It is estimated that heteroaromatic nuclei are the electron transport centers of SIC molecules.