The present work deals with the aggregation behaviour and structure transitions of mixed system of dioctadecyldimethylammonium chloride (DODAC) and dodecylethyldimethylammonium bromide (DDAB) in order to further evaluate its solubilization efficiency of aromatic compounds. Structure transitions and stability of the prepared formulations have been assessed by differential scanning calorimetric (DSC), zeta potential and fluorescence spectroscopy. The vesicle-micelle transition has been analyzed by fluorescence anisotropy measurement at various pH (3.2, 7.2 and 11.2). The mixed surfactant system has further been utilized to enhance the solubility of a hydrophobic moiety i.e. pyrene. Various parameters such as molar solubilization ratio (MSR), partition coefficient (K.), association constant (K-1) and average number of pyrene molecule associated with aggregate (S-M) have been estimated. Present work provides information about the precise vesicle-micelle transition point in a mixed micellar system and takes into account the solubilization selectivity, where vesicles show higher solubilization efficiency as compared to micelles. (C) 2014 Elsevier B.V. All rights reserved.