2,7-Di(halophenyl)-9,9-bisalkylfluorene derivatives for liquid crystal compositions & organic electroluminescent display devices

The invention relates to 2,7-di(halophenyl)-9,9bisalkylfluorene derivatives of formula I and liquid crystal compositions comprising them, and their use in liquid crystal displays and organic electroluminescent display devices (inter alia). [wherein R and R are independently of each other straight-chain or branched alkyl with 8 to 20 C atoms that is optionally mono- or polyfluorinated, and in which one or more non-adjacent CH2 groups are optionally replaced by -O-, -CY =CY - or -C=C-, Y and Y are independently of each other H, F, CI or CN, X is F or CI s is independently of one another 1, 2, 3 or 4, t is independently of one another 0,1, 2 or 3 and the remaining substituents, m and n are as defined herein.