In order to investigate the coordination behaviour of the macrocyclic crown thioether bzo 2-18S6 (2,3,11,12-dibenzo-1,4,7,10,13,16-hexathiacyclooctadecane) and the properties of its metal compounds, the ruthenium and silver complexes [Ru(bzo 218S6)] 2+ and [Ag(bzo 218S6)] + were synthesized. [Ru(bzo 2 18S6)](PF 6 2·2CH 3NO 2 crystallizes in space group P2 1/ c with a=1151.7(4), b=554.1(2), c=2695.8(13) pm, β=100.00(4)°, Z=2 and D calc=1.90 g/cm 3; R=0.072, R w=0.052. The ruthenium center is surrounded by the six sulfur atoms of the ligand in almost ideal octahedral geometry. Reaction of bzo 218S6 with [M(CO) 3L 3] (MCr, Mo, W; LCH 3CN, EtCN) yields the corresponding complexes [M(CO) 3(bzo 2 18S6)], indicating that the crown thioether will not act as a hexadentate ligand, if the metal center carries strongly bound coligands. The tertiarybutyl derivative of bzo 218S6, bubzo 218S6 (2,3,11,12- bis(2′,4′-di-tertiarybutyl-benzo)-1,4,7,10,13,16-hexathiacyclooctadecane), is obtained by template alkylation of [Fe(CO)‘ buS 5’] (‘ buS 5’ 2− = 2,2′-bis(2-mercapto-3,5-di-tertiarybutyl-phenylthio)diethylsulfide(20−)) with bis(β-bromoethyl sulfide, followed by acidic hydrolysis of the primary product [Fe( bubzo 218S6)]Br 2. As the structure of [Fe( bubzo 218S6)]Br 2 remained uncertain, free bubzo 218S6 was reacted with Fe(CF 3SO 3) 2 to give [Fe bubzo 218S6)](CF 3SO 3) 2 which was characterized by NMR spectroscopy.