A novel compound comprising a Ru-tethered polyoxometallate Keggin anion of formula [HNEt(3)](+)-[(Ru{eta(5)-C(5)H(5)}{PPh(3)}(2))(2)(PW(12)O(40))](-) has been synthesised that shows high activity and selectivity in alkyne oligomerisation. In situ IR binding studies using CO confirmed the accessibility of the Ru centre for catalysis. Phenyl acetylene was successfully dimerised under a heterogeneous catalytic regime. Selectivity towards the (E)-enyne, not found in the homogeneous Ru(eta(5)-C(5)H(5))(PPh(3))(2)Cl analogue, was achieved while retaining high a turnover frequency of 225 h(-1).