The present invention relates to the use of (hetero)aryl-substituted acridine derivatives as matrix materials in a light-emitting layer of organic light-emitting diodes (OLEDs) and/or in a blocking layer for electrons in organic light-emitting diodes. The present invention further relates to a light-emitting layer which comprises at least one emitter material and at least one matrix material, wherein the matrix material used is at least one (hetero)aryl-substituted acridine derivative, and to an organic light-emitting diode which comprises at least one inventive light-emitting layer, to an organic light-emitting diode which comprises at least one acridine derivative of the formula (I) in a blocking layer for electrons, and to a device selected from stationary and mobile visual display units and illumination units which comprise at least one inventive organic light-emitting diode.