The invention relates to compounds of the formula (I) in which Y1 and Y2 are each O or, respectively, NRa or NRb, where Ra and Rb are each H or organyl; Z1 to Z4 are each O or S; R11 to R14, R21 to R24 are each Cl, F; where 1 or 2 of the R11 to R14, R21 to R24 radicals may also be CN and/or 1 R11 to R14, R21 to R24 radical may be H; and where, when Y1 is NRa, Z1 or Z2 may also be NRc, where Ra and Rc together are a bridging X group having from 2 to 5 atoms; and where, when Y2 is NRb, Z3 or Z4 may also be NRd, where Rb and Rd together are a bridging X group having from 2 to 5 atoms; to a process for preparation thereof, and to their use as emitter materials, charge transport materials or exciton transport materials.