NOVELTY - Heterocyclic spiro compound (I), is new.    USE - Heterocyclic spiro compound for use in an oligomer, polymer or dendrimer or a composition in electronic device (organic electroluminescent, organic integrated circuits, organic field-effect transistors, organic thin film transistors, organic light emitting transistors, organic solar cells, organic optical detectors, organic photoreceptors, organic field-quench devices, light-emitting electrochemical cells or organic laser diodes) as a hole-blocking material, electron injection material or electron transport material, and for use in formulation (all claimed).    ADVANTAGE - The spiro compound ensures excellent electron-conducting groups, high luminous efficacy to achieve a specific light flux luminance lowest possible voltage, improved processability, handling, efficiency, operating voltage and service life, good solubility and film formation, and provides electronic devices with excellent performance in a reduced cost.    DETAILED DESCRIPTION - Heterocyclic spiro compound of general formula (I), is new.    X=O, S or C(R1)2 group;    Ar'=identically 6-40C aryl group or 3-40C heteroaryl group, which may be substituted by one or multiple R1 radicals;    R1=same or different H, D, F, Cl, Br, I, CHO, C(=O)Ar1, P(=O)Ar1, S(=O)Ar1, S(=O)Ar1, CN, NO2, Si(R2)3, B(OR2)2, OSO2R2, straight 1-40C alkyl, alkoxy or thioalkoxy group or a branched 3-40C cyclic alkyl, alkoxy or thioalkoxy group, which may be substituted by one or multiple radicals R2, where one or multiple non-adjacent CH2 groups are replaced by R2C=CR2, C=C, Si(R2)2, Ge(R2)2, Sn(R2)2, C=O, C=S, C=Se, P(=O)(R2), SO, SO2, O, S or CONR2, which are replaced with one or multiple H-atoms, D, F, Cl, Br, I, CN or NO2 may be replaced with aromatic or heteroaromatic ring system having 5-40 aromatic ring atoms, which can be substituted by one or multiple radicals R2;    R2=same or different H, D, F, Cl, Br, I, CHO, C(=O)Ar1, P(=O)(Ar1)2, S(=O)Ar1, S(=O)2Ar1, CN, NO2, Si(R3)3, B(OR3)2, OSO2R3, straight 1-40C alkyl, alkoxy or thioalkoxy group or branched 3-40 C cyclic alkyl, alkoxy or thioalkoxy group, which may be substituted by one or multiple R3 groups, where one or multiple non-adjacent CH2 groups by C=C, Si(R3)2, Ge(R3)2, Sn(R3)2, C=O, C=S, C=Se, P(=O)(R3), SO, SO2, O, S or CONR3, which may be replaced H atoms, D, F, Cl, Br, I, CN or NO2 group;    Ar1=same or different 5-30C aromatic or heteroaromatic ring system or aromatic ring, which is substituted with R2 radicals, and bind to phosphorus atom through a single bond or a bridge selected from B(R3), C(R3)2, Si(R3)2, C=O, C=NR3, C=C(R3)2, O, S, S=O, SO2, N(R3), P(R3) or P(=O)R3 group;    R3=same or different H, D, F or 1-20C aliphatic, aromatic or heteroaromatic hydrocarbon radical, in which H atoms are replaced by F, and form a mono- or polycyclic, aliphatic or aromatic ring system with two or multiple adjacent substituents R3;    n=0-4;    m=0-3;    o=0-2;    p, q, r, s, t or u=0-1;    E=electron transporting group, substituted by one or multiple radicals R1;    R4=R1 or a group -(Ar')p-E; and    R5=R1 or a group -(Ar')p-E.    INDEPENDENT CLAIMS are included for the following:    (1) a composition, which comprises an oligomer, polymer or dendrimer and organic functional material; and    (2) a method for preparing a compound, which involves preparing spiro bifiuoren backbone, and then introducing a radical having an electron transporting group by coupling reaction.