Cationic arene complexes [Cb*Co(naphthalene)] + (2, Cb* = C 4 Me 4 ) and [Cb*Co(phenanthrene)] + were synthesized by the reactions of [Cb*Co(MeCN) 3 ] + with arenes. The [Cb*Co(anthracene)] + complex was synthesized by the abstraction of the iodide ion from [Cb*CoI] 2 by TlВF 4 in the presence of anthracene. Complex 2 exchanges the naphthalene ligand for other arenes at room temperature.