Interest in metallabenzenes-in which a metal atom formally replaces a CH group in benzene-lies in their aromaticity and ability to mediate organic reactions. A team led by Guochen Jia at the Hong Kong University of Science & Technology has recently developed a convenient way to prepare osmabenzenes (shown; Ph = phenyl). By treating dichloro- or dibromotris(triphenylphosphine)osmium with readily accessible 1,4-pentadiyne-3-ol, Jia's team has made the first air-stable phosphonium salts of metallabenzenes [J. Am. Chem. Soc., 126, 6862 (2004)]. The researchers suggest that the reaction is initiated by coordination of one terminal carbon-carbon triple bond of the dialkyne to osmium, replacing one of the triphenylphospine ligands. Successive nucleophilic attacks on the two carbon-carbon triple bonds by two triphenylphosphines followed by dissociation of the hydroxyl group in the original diyne lead to formation of an osmabenzene phosphonium salt.