NOVELTY - Substituted indolocarbazole compounds (A) are new.    USE - (A) are useful: in organic thin-film transistor; in organic electronic device (claimed); in devices that convert electrical energy into radiation (e.g. a light-emitting diode, light-emitting diode display, light-emitting luminaire and diode laser); in devices that detect signals through electronics processes (e.g. photodetectors, photoconductive cells, photoresistors, photoswitches, phototransistors, phototubes and IR detectors); in devices that convert radiation into electrical energy (e.g. a photovoltaic device and solar cell); in devices that include at least one electronic components including at least one organic semi-conductor layers (e.g. a thin film transistor and diode); and as as oxygen sensitive indicators and luminescent indicators in bioassays.    ADVANTAGE - Electronic devices including an active layer with the compounds described herein, have greatly improved lifetimes. In addition, the lifetime increases are achieved without deleteriously affecting other device properties. Furthermore, the 10 deuterated compounds described herein have greater air tolerance than the non-deuterated analogs. This can result in greater processing tolerance both for the preparation and purification of the materials and in the formation of electronic devices using the materials.    DETAILED DESCRIPTION - Substituted indolocarbazole compounds (A) of formulae (I) and (II) are new.    Ar1 = aromatic electron transporting group;    Ar2 = aryl or aromatic electron transporting group; and    R1, R2 = H, D or aryl.    Provided that (A) has at least one D. INDEPENDENT CLAIMS are also included for:    (1) an organic thin-film transistor comprising: a substrate; an insulating layer (104); a gate electrode (102); a source electrode (106); a drain electrode (108); and an organic semiconductor layer (110) comprising (A), where the insulating layer, the gate electrode, the semiconductor layer, the source electrode and the drain electrode are arranged in any sequence provided that the gate electrode and the semiconductor layer both contact the insulating layer, the source electrode and the drain electrode both contact the semiconductor layer and the electrodes are not in contact with each other; and    (2) an organic electronic device comprising a first electrical contact layer, a second electrical contact layer, and at least one active layer between them, where the active layer comprises (A).    DESCRIPTION OF DRAWING(S) - The figure shows the schematic diagram of organic field effect transistor.    Gate electrode (102)    Insulating layer (104)    Source electrode (106)    Drain electrode (108)    Organic semiconductor layer (110)