The first Ni0 complex with an arene as a six-electron ligand, complex 1 is formed by the displacement of the ethene ligands in [(η1-tBu2PCH2PtBu2)Ni(C2H4)2] by ethyne, which undergoes cyclotrimerization on the phosphane-nickel complex fragment at temperatures below −50 °C (!). The Ni atom in 1 has pseudo-linear coordination to the η1-bound diphosphane ligand and the planar, symmetric benzene ligand.