The photolysis of [Cp″Ta(CO)4] 1 (Cp″ = C5H3tBu2−1,3) and P4 affords Cp″(CO)2Ta(η4−P4) 2, [{Cp″(CO)Ta}2(m̈−η2:2−P2)2] 3 and [Cp3″(CO)3Ta3(P2)2] 4. In a photochemical reaction 2 and [Cp*Nb(CO)4] 5 form [{Cp*(CO)Nb}{Cp″(CO)Ta}(m̈−η2:2−P2)2] 6 and [{Cp*(CO)2Nb} {Cp*Nb}{Cp″(CO)Ta}(m̈3−η2:1:1−P2)2] 7, a compound with the novel m̈3−η2:2:1−P2-coordination mode. The reaction of 2 and [Cp*Co(C2H4)2] 8 leads to [{Cp*Co} {Cp″(CO)Ta}(m̈−η2:2−P2)2] 9, a heteronuclear complex with an „early” and a „late” transition metal. Complexes 2, 3, 7 and 9 have been further characterized by X-ray structure analyses.