Oxophosphonium ions (R2P=O)+ are fascinating chemical intermediates related to the well‐known acylium cations (RC=O)+, and comprise a tricoordinate phosphorus(V) center with a phosphorus–oxygen double bond. Here, we report the synthesis of two oxophosphonium ions stabilized by bulky imidazolin‐2‐imine and imidazolin‐2‐olefin substituents attached to phosphorus. The novel species were characterized by NMR spectroscopy and single‐crystal X‐ray diffraction analysis, and the bonding situation was probed by DFT calculations. Determination of the acceptor number and the fluoride ion affinity revealed that the choice of the substituents has a strong influence on the electrophilicity of the phosphorus center. Additionally, the formation of Lewis base adducts with pyridine derivatives and the reactivity with isopropyl alcohol was explored. Free at last! Two Lewis base free oxophosphonium ions have been synthesized and structurally characterized. The electrophilicity of the phosphorus center strongly depends on the choice of the π‐donating substituents at phosphorus.