In conclusion, ligand exchange at carbon enabled the isolation of the so far elusive cyanoketene anion, [NC3O] -, a rare, but stable member of the family of 5-atomic cumulenes. The anion exhibits a bent structure in solid-state, yet with an extremely flat energy potential surface for its bending to linearity. Computational studies reveal an ambiguous bonding situation with highly delocalized orbitals, which is best described by a combination of resonance structures. The thermal stability of the anion together with its intrinsic nucleophilicity enables its facile conversion with various abundant small molecules and thus the atom-economic synthesis of a series of complex organic molecules. This reactivity makes the cyanoketene anion 2 to an interesting precursor to nitrogen and oxygen containing organic compounds, also of industrial value. Furthermore, it represents an excellent model system for comparative studies of its chemistry in solution phase, with its reactivity in gas-phase or under matrix isolation conditions to gain further insights into differences and similarities between astrochemistry and traditional organic synthesis in solution.