The present application relates to spirobifluorene derivatives of a formula (I), to the use thereof in electronic devices, especially in organic electroluminescent devices (OLEDs), where they may be used in hole-transporting function, and to processes for preparing said derivatives. The compounds have one or more properties selected from very good hole-conducting properties, very good electron-blocking properties, high glass transition temperature, high oxidation stability, good solubility and high thermal stability.