The first C 3 -symmetric 44-core-valence-electron triangular palladium clusters, [{(SAr')(PAr 3 )Pd} 3 ] + , have been synthesized by activation of the C À S bond of isothioureas. Owing to delocalized metal-metal bonding, these stable complexes are the first noble-metal analogues of the paromatic cyclopropenyl cation [C 3 H 3 ] + , with their all-metal aromaticity involving d-type atomic orbitals.