NOVELTY - An electroactive composition comprises: a deuterated first host material comprising a deuterated aromatic diamine compound, and an electroluminescent dopant material.    USE - As electroactive composition useful in organic light-emitting device (claimed) such as organic electroactive electronic devices including devices that convert electrical energy into radiation (e.g. light-emitting diode, organic light emitting diode (OLED) display, and diode laser), devices that detect signals through electronics processes (e.g. photodetectors, photoconductive cells, photoresistors, photoswitches, phototransistors, phototubes, infrared (IR) detectors, and biosensors); devices that convert radiation into electrical energy (e.g. photovoltaic device, and solar cell), and devices that include electronic components that include organic semi-conductor layers (e.g. transistor such as thin film transistor (TFT) and diode).    ADVANTAGE - The electroactive composition includes deuterated aromatic diamine compound as host material. The deuterated aromatic diamine host material has solubility in toluene of greater than or equal to 0.6 wt.%. The first deuterated host material has a highest occupied molecular orbital (HOMO) energy level of less than or equal to -5.6 eV or lowest occupied molecular orbital (LUMO) deeper than -2 eV. The electroactive compositions are useful as solution processible electroactive compositions for organic light emitting diode (OLED) devices, where the resulting devices have high efficiency and long lifetimes.    DETAILED DESCRIPTION - An electroactive composition comprises: a deuterated first host material comprising a deuterated aromatic diamine compound of formula (Ar1)( Ar2)N-Q'-(-N(Ar3)(Ar4))m (I), and an electroluminescent dopant material.    Ar1-Ar4=aryl;    Q'=multivalent aryl groups, or a group of formula T'1-T'-T'1;    T'=(CR')a, Si(R'1)2, S, SO2, PR'1, PO, PO2, BR'1, or R'1;    T'1=phenyl-diyl;    R'1=alkyl, or aryl;    R'=H, D, or alkyl;    a=1-6;    m=0-6.    An INDEPENDENT CLAIM is included for an organic light-emitting device comprising: two electrical contact layers with an organic electroactive layer between them, where the electroactive layer comprises a deuterated first host material comprising the deuterated aromatic diamine compound (I), and an electroluminescent dopant material.