NOVELTY - 4,4'-Substituted spirobifluorene compounds (I), are new.    USE - (I) are useful as a host material for fluorescing or phosphorescing dopants, preferably for phosphorescing dopants, emitting material (dopant), hole transport material, hole injection material and/or an electron transport material in electronic devices, which is an organic electroluminescent device, preferably organic field-effect-transistors, organic thin-film transistors, organic light-emitting transistors, organic integrated circuit, organic solar cells, organic field-quench-devices, light-emitting electrochemical cells, organic laser diodes or organic photoreceptors (all claimed).    ADVANTAGE - (I) provide electronic devices with improved durability, thermal stability and quantum efficiency.    DETAILED DESCRIPTION - 4,4'-Substituted spirobifluorene compounds of formula (I), are new.    R = F, CN, NO2, Ar1NAr12, NAr12, C(=O)Ar1, C(=O)R2, P(=O)Ar12, S(=O)Ar1, S(=O)2Ar1, -CR2=CR2, or a mono- or polycyclic (hetero)aryl ring with 5-60 aromatic ring atoms (optionally replaced with one or more non-aromatic R1), where two Ar1 bonded to N or P are connected through a single bond or a bridge comprising B(R2), C(R2)2, Si(R2)2, C=O, C=NR2, C=C(R2)2, O, S, S=O, SO2, N(R2), P(R2) or P(=O)R2;    R1 = 1-40C-alkyl, 1-40C-alkoxy, 1-40C-thioalkoxy, cyclic 3-40C-alkyl, 3-40C-alkoxy, 3-40C-thioalkoxy, 2-40C-alkenyl (all optionally replaced with R2, where one or two non-adjacent CH2 groups are optionally replaced by R2C=CR2, C?=C, Si(R2)2, C=O, C=S, C=NR2, P(=O)(R2), SO, SO2, NR2, O, or S and one or more H atoms are optionally replaced by D, F, Cl, Br, I, CN or NO2), H, D, F, Cl, Br, I, OH or CN, where the R1, which is in vicinal position to R (where R is (hetero)aryl ring system) is a bivalent unit, which is connected with R;    Ar1 = (hetero)aryl with 5-30 aromatic ring atoms optionally substituted with R1; and    R2 = H, D, F, CN, or aliphatic, (hetero)aryl 1-20C-hydrocarbon (in which one or more H atoms are optionally replaced by F, CN, 1-40C-alkyl, 1-40C-alkoxy, 1-40C-thioalkoxy, cyclic 3-40C-alkyl, 3-40C-alkoxy or 3-40C-thioalkoxy, where two or more adjacent R2 groups are covalently bonded or R2 is connected through one or more bivalent aliphatic hydrocarbon unit, when R2 is (hetero)aryl hydrocarbon).    INDEPENDENT CLAIMS are included for:    (1) the preparation of (I);    (2) a mixture comprising (I) and at least a further compound; and    (3) a formulation or solution comprising (I) and at least a solvent.