Alkynylborate-stabilized triorganolead cations I (R = Et, CHMe2, R1 = Me, Bu, CMe3, Ph) were prepd. from Me2Pb(C.tplbond.CR1)2 and R3B. The x-ray crystal structure was detd. for I (R = CHMe2, R1 = Me), which also decompd. by intramol. rearrangement to give II and in the presence of MeOH to give III. The nature of the Pb+-carbon-carbon triple bond coordination in these complexes was discussed.