NOVELTY - Substituted naphthalene compounds (I) are new.    USE - (I) or their oligomers, polymers or dendrimers are useful as matrix material for fluorescent dopants or phosphorescent compounds or as emitting material (dopant), a hole transport material, a hole injection material or as electron transport material in electronic device, preferably organic electroluminescent device, organic field-effect-transistors, organic thin-film transistors, organic light-emitting transistors, organic integrated circuits, 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 - Substituted naphthalene compounds of formula (I) are new.    X = C(R)2, Si(R)2, NR, C=O, C=S, C=NR, COO, CONR, O, S, SO, SO2, P(=O)R or C(=CR2);    Ar1 = 5-60 membered (hetero)aryl (optionally substituted by one or more R);    b-d = 0-2;    a, e, v, x, y = 0 or 1, where the sum of the values of the indices v is at least 2, x+y is greater than or equal to 1, a+b+c+d+e is greater than or equal to 2, and all the free bonding sites are optionally substituted with R; and either    R = linear 1-40C-alkyl, -alkoxy or thioalkoxy, linear 2-40C-alkenyl, branched 3-40C-alkyl, -alkoxy or thioalkoxy (all optionally substituted with one or more R1, and where one or more adjacent or non-adjacent CH2 groups are optionally replaced by R1C=CR1, Si(R1)2, Ge(R1)2, Sn(R1)2, C=O, C=S, C=Se, C=NR1, P(=O)(R1), SO, SO2, NR1, O, S, COO or CONR1), H, D, F, Cl, Br, I, N(R1)2, CN, NO2, Si(R1)3, B(OR1)2, C(=O)R1, P(=O)(R1)2, S(=O)R1, S(=O)2R1, OSO2R1, or 5-60 membered (hetero)aryl, (hetero)aryloxy or (hetero)aralkyl (all optionally substituted with one or more R1); and    R1 = 1-40C-aliphatic, aryl or heteroaryl organic residue (where one or more H atoms are optionally replaced by D, F, Cl, Br, I, CN, OR2, SR2 or N(R2)2, and one or more adjacent or non-adjacent CH2 groups are optionally replaced by R2C=CR2, COO or CONR2), H, D, F, Cl, Br, I or CN; and    R2 = 1-20C-aliphatic, aryl or heteroaryl organic residue (where one or more H atoms are optionally replaced by D or F), H or D; or    two or more R, R1 or R2 = mono-or poly-cyclic, aliphatic or aromatic ring system.    INDEPENDENT CLAIMS are included for:    (1) the preparation of (I);    (2) oligomers, polymers or dendrimers of (I);    (3) a formulation comprising (I) or their oligomers, polymers or dendrimers, and at least one solvent; and    (4) an electronic device, preferably organic electroluminescent device, organic field-effect-transistors, organic thin-film transistors, organic light-emitting transistors, organic integrated circuits, organic solar cells, organic field-quench-devices, light-emitting electrochemical cells, organic laser diodes or organic photoreceptors comprising (I) or their oligomers, polymers or dendrimers.