The stannylated allenes1 and2 were prepared by 1,1-organoboration of two equivalents of bis(trimethylstannyl)ethyne (4) with one equivalent of triethylborane or ferrocenyl-dimethylborane. The organometallic-substituted alkenes5 and6 could be obtained from1:1 reactions. 4-(9-Borabicyclo[3.3.1]non-9-yl)-1,1,4,4-tetrakis(trimethylstannyl)-1,2-butadiene (3) was obtained from the reaction of4 with dimeric 9-borabicyclo[3.3.1]nonane. The molecular structures of the allenes1 and3 were determined by X-ray analysis. In both cases, the structural parameters of the (Me 3 Sn) 2 CBR 2 unit indicate SnC hyperconjugation, and this model is supported by the small magnitude of the coupling constants 1 J( 119 Sn, 13 C), by the increased 11 B nuclear shielding as well as by the unusual changes in the δ 119 Sn values in going from the solution to the solid state. A fairly complete set of signs of coupling constants n J( 119 Sn, 1 H) n J( 119 Sn, 13 C)and n J(Sn, Sn) was derived for the allene3 using 2D 13 C/ 1 H and 119 Sn/ 1H heteronuclear shift correlations.