The silver ion-based supramolecular adducts bearing long alkyl chains (Cn-Phen: n (carbon number of alkyl chain)=12, 14, 16, 18) were prepared by reaction of phenazine and silver alkylsulfonates. Their liquid crystalline behavior was studied by differential scanning calorimetry, polarizing microscopy, and temperature-dependent X-ray diffraction techniques. Each of the adducts exhibits three mesophases with layer structures; an unidentified smectic phase (Sx), smectic C (SC), and smectic A (SA) phases. Furthermore, it was found that each of the layers has a two-dimensional silver ion sheet sandwiched above and below by two aliphatic sheets.