Lipophilic polyelectrolyte gels capable of large swelling in low-polar solvents (3 ≤ ε ≤ 10) were developed by Ono et al. (Nature Mater., 2007), where ε is the dielectric constant. These gels were prepared by introducing tetraphenylborate as a lipophilic anion (tetrakis(3,5-bis(trifluoromethyl)phenyl)-borate; TFPB-) and tetraalkylammonium with long alkyl chains as a lipophilic cation (tetra(n-butyl) ammonium; TBA+) into a poly (octadecyl acrylate) (pODA) backbone chain. Here, we investigated the structure of the lipophilic polyelectrolyte gels and corresponding polymer solutions in CH2Cl2 with small-angle neutron scattering (SANS) and dynamic light scattering (DLS). From SANS, it was revealed that individual pODA chain is regarded as a rod with the cross-section radius of 15 Å and the length of ca. 160 Å and is little changed by introduction of charges or cross-linking. In addition to this, it was revealed from SANS measurements that the second virial coefficient of pODA in CH2Cl2 was positive. In combination with DLS measurements, we observed several characteristic features similar to polyelectrolyte aqueous systems such as (i) the clear appearance of slow diffusional motion in polymer solutions, (ii) an increase of diffusion coefficient in gels, and (iii) an increase of osmotic modulus in solutions and gels when ionic groups are incorporated in pODA. These experimental findings clearly show that [TBA+][TFPB-] dissociates enough and pODA, accompanying these ionic groups, acts as a polyelectrolyte even in a low-polar solvent such as CH2Cl2 (ε = 8.9). It is concluded that the good compatibility of pODA with CH2Cl2 and the introduction of dissociable ionic groups into pODA result in high-swelling capability of the lipophilic polyelectrolyte gels.