Stable vesicles are formed in a 1.4 wt% solution comprising a 1:3 mixture of the anionic photodestructible surfactant sodium 4-hexylphenylazosulfonate (C(6)PAS) and inert cationic cetyltrimethylamonium bromide (CTAB). UV irradiation drives an irreversible breakdown of the mixed C(6)PAS/CATB vesicles, owing to the selective degradation Of C(6)PAS. A light-induced transition from small spherical-like polydisperse vesicles to long needle-like aggregation is observed.