Treatment of 3-methyl-3-vinylcyclopropene (1) with 2 equiv. of lithium diisopropylamide followed by 2 equiv. of Me 3 ECl (E = Si, Ge, Sn) afforded 1,2-bis-(Me 3 E)-3-methyl-3-vinylcyclopropenes (2-4) in moderate to good yield. The He(I) PE spectra of2-4 have been recorded and interpreted in terms of inductive and conjugative abilities of the organometallic substituents, taking into account differences in the nature and the localization properties of the highest occupied levels in the parent molecule.