Previous reports on the generation of cyanoketene 1 or its anion 2 relied on thermal decomposition reactions or irradiation or chemical ionization under gas phase or matrix isolation conditions. Neither of these methods allowed an isolation of 2 in a preparative scale. To generate and isolate the cyanoketene anion, we therefore selected a synthetic method only previously developed in our group to access anionic ketenes. This method makes use of a phosphine-by-carbon monoxide ligand exchange at the central carbon atom in metalated ylides, to provide mild access to ketenyl anions, allowing their first gram-scale isolation and structure characterization. The simplicity of this method motivated us to probe its applicability to the isolation of the elusive cyanoketene anion by reaction of the cyano-functionalized potassium yldiide 3-K with carbon monoxide (Fig. ). To mimic the free anion as assumed to be present in the ISM, any interfering cation-anion interactions were excluded by encapsulation of the cation through addition of crown ethers or cryptands. Stirring the metalated ylide 3-K and 18-crown-6 in THF under an atmosphere of CO led to the precipitation of the cyanoketene anion complex, 2(K•18-crown-6), which was isolated as a colorless solid in a good 78% yield and unambiguously characterized by different spectroscopic and crystallographic methods. Albeit the starting yldiide 3-K is unlikely to exist in space, an analog reactivity may arise from small ammonium ylides formed from cyanocarbene, NC-C-H, or aminoacetonitrile, NH2-CH2-CN, which have already been detected in space. The subsequent generation of the carbanionic species might occur by ionizing radiation such as galactic cosmic rays. The anion in 2(K•18-crown-6) features three distinct signals in the C NMR spectrum, with the signals for the CO and CN carbon atoms appearing downfield at 116.1 and 120.2 ppm, respectively. In contrast, the central carbon atom C1 exhibits a remarkably high-field shifted signal at -13.4 ppm, which clearly indicates a high charge concentration at this site in agreement with the resonance structure 2a. These NMR features compare well with those of iminopropadienones (R-NC3O), which however have been described as linear species. To unambiguously determine the structure of 2 and gain first insights into the bonding situation, X-ray diffraction (XRD) analyses of single crystals of 2-K formed under different conditions (temperature, coligands) were conducted. Various single crystals -albeit being of high quality -showed severely disordered structures of 2 within the void between the cations. This disorder prevented a clear elucidation of the anion structure, above all a differentiation between the oxygen and nitrogen position and between a linear or bent geometry (see the Supporting Information). This could be circumvented by using [2,2,2]cryptand to fully encapsulate the potassium cation and prevent its unselective coordination to either the nitrogen or oxygen end of 2. In the salt 2(K•[2,2,2]cryptand) (Fig. ), the anion features a planar, but bent structure with a large angle of 166.4(2)° at the central carbon atom C1, which clearly argues against a regular cumulene structure (2c, 2d, Figure ). This contrasts previous calculations on the anion and the solid-state structure of the isoelectronic carbon suboxide, C3O2, which were both reported to be linear. However, the structure of carbon suboxides also showed large vibrational ellipsoids for the central carbon and oxygen atoms, indicative for a slight bending of the molecule, which was also confirmed by computational studies. Similarly, 2(K•[2,2,2]cryptand) features large thermal ellipsoids -in particular for the oxygen and nitrogen atom -suggesting a high degree of flexibility in the C-C-C linkage.