By ionic exchange pure tetramethylammoniumcyanate [N(Ch(3))]4OCN was synthesized for the first time. Single crystals were investigated on a 4-circle-diffractometer. Structure solution and refinement was done in Pmn2(1). The structure may be derived from the CsCl-type with linear, non-symmetric cyanate-anions and tetrahedral, slightly distorted tetramethylammonium-cations Vibrational spectra confirm the distortion of the cation which can be caused by weak O...H(C)-interactions.