Abstract Phospholipid 1, bearing a benzophenone probe constrained in the middle of the double layer, has been synthesized by condensation of the bis (imidazolide) 16 with the CdCl 2-complex of the lysophosphatidylcholine 5. It forms photosensitive liposomes and vesicles, alone and with dimyristoylphosphatidylcholine (DMPC).