Vinylallenes were prepared in high yields by the Wittig−Horner reaction of 1-lithio-1,3-dienyl phosphine oxides with aldehydes. 1-Lithio-1,3-dienyl phosphine oxides were generated in situ from lithiation of 1-iodo-1,3-dienyl phosphine oxides, which were obtained by iodination of α-phosphinozirconacyclopentadienes. As a whole, a vinylallene is synthesized from two different alkynes and one aldehyde