Treatment of [C5H5IrX2]n (2: X = Cl; 3: X = Br) with CH2=CHtBu in the presence of Na2CO3–iPrOH gives, besides the bis(olefin) complex [C5H5Ir(CH2=CHtBu)2] (4), the doubly vinyl-bridged iridium(II) compound {[C5H5Ir(μ-η1,η2-CH=CHtBu)]2} (5). The related binuclear complex {[CH2(C5H4)2][Ir2(μ-η1,η2-CH=CHtBu)2]} (9) was obtained from {[CH2(C5H4)2][IrBr2]2}n (8) and CH2=CHtBu–Na2CO3 in ethanol and characterized by an X-ray structure analysis (monoclinic, C2/c (No. 15), a = 20.050(8), b = 8.843(1), c = 24.25(1) Å, β = 99.53(2)°, V = 4241 Å3, Z = 8, R = 0.032, Rw = 0.041). Protonation of both 5 and 9 with HBF4•OEt2 yields the BF4 salts of the unsymmetrical hydridometal cations 10 and 11 in which the vinyl bridges are still intact. The reaction of the binuclear bis(cyclooctene)metal compounds {[CH2(C5H4)2][Rh(C8H14)2]2} (14) and {[CH2(C5H4)2][Rh(C8H14)2][Ir(C8H14)2]} (17) with bromine yields almost quantitatively the polymeric (or oligomeric) dibromo derivatives 16 and 18, which could, however, not be converted to vinyl bridged complexes by treatment with CH2=CHtBu–Na2CO3–ROH. Keywords: iridium complexes, C-H activation, bridging vinyl ligands, cationic hydridometal complexes, heterometallic complex.