The ternary azo dye/water/methanol systems were investigated by polarized microscopic and small-angle neutron scattering methods. The formation and structures of supramolecular self-assemblies were discussed in relation to methanol content in isotropic and anisotropic systems. Stripelike assemblies and their piles were constructed in the systems with low methanol content. On the other hand, fibrils having linear molecular arrangement and their bundles were formed at high methanol content. Moreover, liquid crystals in anisotropic gels consisted of an organization of stripes or fibrils. Absorption spectra were measured in order to confirm the formation of supramolecular assemblies.