Mononuclear and binuclear compounds [(C 5 Me 5 )Ru(η 6 -arene)PF 6 and [(C 5 Me 5 Ru) 2 (η 6 ,η 6 -arene)](PF 6 ) 2 were prepared by reacting (C 5 Me 5 )RuCl 2 , the arene and silver acetate with subsequent addition of NH 4 PF 6 , for arene = phenanthrene, chrysene, triphenylene, fluorene, bifluorene, biphenyl and 4,4′-biphenyl. The mononuclear compounds were also prepared for arene = naphthalene, anthracene, pyrene and coronene. The 1 H and 13 C NMR spectra are reported. By cyclic voltammetry all compounds show a first reduction potential that is considerably more positive compared with the free arene. The first cathodic wave is irreversible for a wide range of scanning speeds. However, the mononuclear coronene and the binuclear phenanthrene compounds show reversibility. The crystal structure of [(C 5 Me 5 )Ru(η 6 -chrysene)]PF 6 ·0.5 Me 2 CO was determined by X-ray diffraction (3797 unique observed reflexions, R = 0.098). Crystal data: a = 1689.2(2), b = 1524.0(8), c = 2263.5(3) pm, β= 107.22(1)°, space group P2 1 /n, Ζ = 8. Crystallographically independent, two cations [(C 5 Me 5 )Ru(η 6 -chrysene)] + and two anions PF 6 - are present, but their structures are essentially equal. The [C 5 Me 5 Ru] + unit is bonded to one of the terminal benzene rings of the chrysene in a sandwich manner; the rings bonded to Ru are nearly coplanar. The PF 6 - ions and the C 5 Me 5 rings exhibit strong thermal vibrations.