Chemical labeling and surface modification of diblock polymer vesicles is of interest due to their potential use as drug delivery systems or mimics of living cells. We report on the use of a one-pot two-phase oxidation reaction specific to the terminal hydroxyl group of PEO. IR spectra of the oxidized product show the specific conversion of the primary alcohol into its carboxylic acid. Subsequent amination of the polymer results in the specific modification of the terminal hydroxyl of PEO based block copolymers. The attachment of fluorophores, noradrenaline and angiotensin to the surface of block copolymer vesicles is characterized by IR spectroscopy, UV absorbance, and confocal microscopy. The modification of the polymer end group changes the chemical groups presented on the surface of the vesicle and is a necessary step to determine the efficacy and resulting colloidal behavior of modified vesicles as drug delivery systems.