Transition-metal-catalyzed dehydrocoupling of tert-butylferrocenylphosphine-borane (2) with [{Rh(μ-Cl)(1,5-cod)}2] (cod = cyclooctadiene) as the catalyst gave the homocoupled product [Fc(tBu)(H)P(BH2)P(Fc)(tBu)(BH2X)] [3; Fc = Fe(C5H5)(C5H4), X = H/Cl], while cross-dehydrocoupling with the tertiary phosphine-boranes P(tBu)(nBu)2(BH3) (2a) and PPh(nBu)2(BH3) (2b) using [Rh(1,5-cod)2]OTf (OTf = trifluoromethanesulfonate) gave the first cross-dehydrocoupled products reported to date, [Fc(tBu)(BH3)P(BH2)P(tBu)(nBu)2] (4) and [Fc(tBu)(BH3)P(BH2)PPh(nBu)2] (5), in moderate yields. Compounds 2-5 were characterized by NMR spectroscopy (¹H, 13C, 31P, and 11B), IR spectroscopy, mass spectrometry, and single-crystal X-ray structure determination. [ABSTRACT FROM AUTHOR]