Base catalyzed addition of 1-vinylimidazole to primary and secondary phosphines affords tertiary phosphines with terminal 1-imidazolyl substituents C3H3N2 in high yields. The X-ray structure of the oxide Ph2P(O)-(CH2)(2)-1-C3H3N2 has been determined (space group Pi). By selective N-protonation and protected group N-quaternization novel cationic phosphines, e.g. 2a, 2b, 9 and 10, with peripheral 1-imidazolium groups are obtained. These are interesting ligands for catalytic reactions in biphasic systems containing ionic liquids as polar phase and may be employed in, hydroformylation of long-chain olefins like 1-octene.