An unprecedented, 22-valence-electron triple-decker sandwich complex [(Cp*Mo)₂{μ-η⁶:η⁶-B₄H₄Ru₂(CO)₆}], 2, has been prepared. In an effort to generate analogous triple-deckers with group 6 metal carbonyl fragments in the middle deck, we have isolated [(Cp*MoCO)₂(μ-H)₂B₄H₄], 3, that provides the first direct evidence for the missing link between [(Cp*MoCl)₂B₃H₇] and [(Cp*Mo)₂B₅H₉] clusters.