Amphilphilic tetraphenylporphin derivatives having four dialkylglycerophosphocholine groups on the ring plane (lipid-porphyrins) form spherical unilamellar vesicles of diameter ca. 100 nm in water; the vesicles composed of lipidâporphyrinatoiron(II)â1-dodecylimidazole (DIm), can bind dioxygen reversibly in aqueous medium.