[η-(Phenyl-ethyn-yl)cyclo-penta-dien-yl](η-tetra-phenyl-cyclo-butadiene)cobalt(I).

In the title compound, [Co(C(13)H(9))(C(28)H(20))], the Co atom is sandwiched between cyclo-penta-dienyl and cyclo-butadienyl rings that are inclined at a dihedral angle of 2.6 (3)°. The four phenyl rings are tilted with respect to the cyclo-butadienyl plane so that the C(4)Ph(4) unit constitutes a four-bladed propeller.