The application relates to liposomal nanovesicles comprising porphyrin-lipid conjugates within the liposomal lipid bilayer. Said porphyrin-lipid conjugate comprise porphyrins that are modified with a —CH(R1)—O—R2 group and that chelate a metal ion. Such modifications of the porphyrin allow for ordered assembly in the lipid bilayer of the nanovesicles while resulting in a bathochromic shift in the wavelength of light absorbed by the porphyrin chromophore. These nanovesicles can be used for photothermal therapy, photodynamic therapy, photoacoustic imaging and fluorescence imaging. The application also teaches methods for preparing the porphyrin-lipid conjugates and the nanovesicles.