We have investigated the phase behavior and characterized the microstructure of the phases that result from mixing of alkyltrimethylammonium hydroxides C x TAOH (x = 10.8) with 2-hydroxy 1-carboxy-naphthoate. We compare the results of this work with the published one of alkyltrimethylammonium 2-hydroxy-1-carboxy-naphthoate (C x TA 2,1 HCN, x = 16.14 or 12) . With increasing counter-ion surfactant ratio r we observed transition from the isotropic L 1 -phase to multilamellar vesicles (MLV) L α -phase. The single phases are separated by a two phase L 1 /L α region. The phases were characterized with FF-TEM, rheological and SANS measurements. For 100 mM solution of either C 8 TAOH/2,1 HNC or C 1 0TAOH/2,1 HNC, both MLV phases behave like a weak gel and have a yield stress value. It is thus shown that it is possible to prepare viscoelastic surfactant solutions with a small yield stress value from single chain surfactants with decyl or octylchain.