A compound of formula [I]: X-R [I] wherein X represents the group: and R is either (i) represented by the formula [II] wherein n is 1 or 2, and the or each R7 group is independently selected from the group consisting of
hydrogen and
halogen atoms, cyano, nitro, mercapto, carbonyl and
sulfone groups, and optionally substituted
alkyl, haloalkyl, hydroxyalkyl,
aryl, alkoxy, aryloxy, alkylamino, arylamino, alkylthio, arylthio, ester, siloxy,
cyclic hydrocarbon and heterocyclic groups; or (ii) is selected from the group consisting of optionally substituted
alkyl, hydroxyalkyl,
aryl,
cyclic hydrocarbon and heterocyclic groups; wherein in each case R1-R6 are each independently selected from the group consisting of
hydrogen and
halogen atoms, cyano, nitro, mercapto, carbonyl and
sulfone groups, and optionally substituted
alkyl, haloalkyl, hydroxyalkyl,
aryl, alkoxy, aryloxy, alkylamino, arylamino, alkylthio, arylthio, ester, siloxy,
cyclic hydrocarbon and heterocyclic groups. The compounds are useful as hole-transporting materials in
electroluminescence devices.