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Two-dimensional MXenes, with being the most prominent member, show properties that make them promising for a manifold of applications, including electrodes in light-emitting diodes, solar cells, and field-effect transistors based on organic semiconductors. In these cases, the work function of MXenes plays an important role in the energy level alignment to the subsequently deposited organic layer, as it determines the electron and hole injection barriers. Therefore, methods for controlling the work function should be developed. We demonstrate that, by using thin layers of (metal-)organic donor/acceptor molecules, the work function of can be tuned over a range of eV. This enables tuning the energy level alignment to a subsequently deposited organic semiconductor, all the way from intrinsic Fermi level pinning at the highest occupied molecular energy level (minimal hole injection barrier …