The interaction between cationic gemini hexanediyl-1,6-bis(dimethylcetylammonium bromide) (16-6-16, abbreviated as G6) with conventional cationic cetylpyridinium chloride (CPC), anionic sodium bis(2-ethyl hexyl)sulfosuccinate (AOT) and nonionic polyoxyethylene 10 cetyl ether (Brij56) in aqueous medium has been investigated at 25 degrees C. Different physicochemical properties such as critical micelle concentration (cmc), surface excess concentration (Gamma(max)), minimum area per molecule (A(min)), and interaction parameters (beta(m), beta(sigma)) as well as other thermodynamic and micellar properties have been determined. The interfacial and bulk behaviors were explored using theoretical models of Clint, Rubingh, Rosen, Motomura, and Maeda for justification and comparison of results of different binary combinations with the geminis of alkanediyl-alpha,omega-bis(dimethylcetylammonium bromide) series. Synergism was observed in all the binary combinations in the micelle and at interface with lowering of packing parameter due to slight expansion of A(min). The results of the present study could be of interest for selection of surfactant mixtures for surfactant-enhanced remediation (SER) of soils and aquifers contaminated by hydrophobic organic compounds (HOCs).