Layered perovskite oxides have attracted considerable attention due to their potential application in photoelectricity and catalysis. The unique character of layered perovskites as ion-exchange materials provides the possibility of creating structural diversity. A new ion-exchange reaction in aqueous solution was observed in layered oxide gamma-Bi₄V₂O₁₁. When employed in ion exchange, gamma-Bi₄V₂O₁₁ is converted into the scheelite-type phase (ABO₄) by selectively discarding Aurivillius-type sheets, and is also converted into the A2X3 phase by selectively dissolving perovskite-like layers. Metal-doped BiVO₄ and Bi₂O₃ were obtained using such an ion-exchange reaction.