Currently, the investigation on the interaction of cationic surfactants with proteins attract the wide attention of researchers. Proteins participate in the majority of important biological processes; therefore, they are essential for a living organism. The addition of proteins to a surfactant solution can significantly modify the adsorption layer properties at liquid/fluid interfaces. In turn, surfactants can markedly affect the conformational behaviour of proteins. Therefore, in this study, the cationic amphiphiles triallyldodecylammonium bromide and triallyltetradecylammonium bromide have been synthesised. Their aggregation behaviour in an aqueous solution, solubilisation capacity towards the hydrophobic azo dye and complexation with bovine serum albumin (BSA) were evaluated. The lower homologue has demonstrated an unusual two-step aggregation behaviour, controlled morphology aggregates and various solubilisation capacities for Orange OT. The increase in the length of the hydrocarbon tail from dodecyl to tetradecyl has resulted in the disappearance of the second critical point and the enlargement of the particle size. Both of the amphiphiles that were investigated effectively interacted with BSA and were bound to the tryptophan amino acid residue of the protein. For surfactants/BSA systems, it was shown that by varying the length of the hydrophobic tail, the dominance of the various types of interactions can be achieved.