NOVELTY - An electroactive material comprises fluoranthene derivative.    USE - The electroactive material is useful for preparing electronic device (claimed), e.g. organic light emitting diodes (OLED); devices that convert electrical energy into radiation (e.g. a light-emitting diode, light-emitting diode display, light-emitting luminaire, or diode laser); devices that detect signals through electronics processes (e.g. photodetectors, photoconductive cells, photoresistors, photoswitches, phototransistors, phototubes, and infrared (IR) detectors); devices that convert radiation into electrical energy (e.g. a photovoltaic device or solar cell); and devices that include electronic components that include organic semi-conductor layers (e.g. a thin film transistor or diode). The electroactive material and fluoranthene derivatives are useful in applications such as oxygen sensitive indicators and as luminescent indicators in bioassays.    ADVANTAGE - When the fluoranthene derivatives are used by themselves or in conjunction with other cohosts, they can provide improved efficiency and lifetime in OLED devices. The fluoranthene derivatives have high triplet energies and highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) levels appropriate for charge transport, making them excellent host materials for organometallic emitters.    DETAILED DESCRIPTION - An electroactive material comprises fluoranthene derivative of formula I or III.    R1-R10=the same or different, selected from H, D, alkyl, silyl, aryl, deuterated alkyl, deuterated silyl, and deuterated aryl; with the proviso that no more than one of R1-R10 is biphenyl and at least two of R1-R10 have formula II;    Ar'=selected from phenyl, naphthyl, heteroaryl, spirofluorenyl, and its deuterated analogs;    R11=the same or different at each occurrence, and selected from D, alkyl, silyl, aryl, deuterated alkyl, deuterated silyl, and deuterated aryl, where adjacent R11 groups can join to form a fused aromatic ring or fused deuterated aromatic ring;    m=0-4;    n=1-5;    asterisk=point of attachment; and    R1a-R10a=the same or different and are selected from H, D, alkyl, silyl, aryl, deuterated alkyl, deuterated silyl, and deuterated aryl; with the proviso that at least one of R1a-R10a includes a spirofluorene group or its deuterated analog.    An INDEPENDENT CLAIM is included for an electronic device comprising electroactive layer positioned between two electrical contact layers, where the electroactive layer comprises fluoranthene derivative of formula I or III.