(C5Me5)2Y(η3-C3H5) reacts with 9-borabicyclo[3.3.1]nonane, 9-BBN, to form single crystals containing both a borane-substituted allyl complex, (C5Me5)2Y[η3-C3H4(BC8H14)], and a borohydride, (C5Me5)2Y(μ-H)2BC8H14, that can be synthesized directly from 9-BBN and the yttrium hydride, [(C5Me5)2YH]x.