Strategic designing catanionic system that leads to vesicle formation is advantageous if one of the components is hydrotropic ‘drug’. Vesicles are size-selective filters that offer passive diffusion of small molecules including drugs and are the best alternatives to liposomes and niosomes. Drug molecules can be carried irrespective to their polarity in vesicles cage/bilayer, which makes them a convenient drug delivery vehicle. Herein we have investigated concentration/composition dependent catanionic vesicles through synergistic interactions between cationic gemini surfactants (GS) and hydrotropic drug, diclofenac sodium (DS). Variables studied to get shape and size-dependent catanionic vesicles includes: alkyl chain length of GS and concentration of DS. We used spectroscopic probes to study the microscopic interactions, dynamic light scattering (DLS) to determine the size and transmission electron microscopy (TEM) and small angle neutron scattering (SANS) to determine the exact shape and size of the vesicles. This work could be of interest in the field of drug delivery as the possible new age nano-carriers.