[Ni(dmit)2]− salt with flexible supramolecular cation rotator

[Ni(dmit)2]− salt (dmit2− 2-thioxo-1,3-dithiole-4,5-dithiolate) with flexible supramolecular cation (4-cyanomethylanilinium)(dibenzo[18]crown-6) has been synthesized and investigated its structure, magnetism and rotation. The comparable large steric hindrances limit the rotation of cyanomethyl group to result in no phase transition occurred. Magnetic and potential energy calculations by DFT method were consistent with the magnetic and structure measurements.