We present the preparation of the electron-doped quasi-two dimensional quantum antiferromagnet (CuCl)LaNb₂O₇by two step-wise topochemical reactions. The first step involves a reductive fluorination of the insulating layered perovskite RbLaNb₂O₇ using polytetrafluoroethylene that allows electric conduction in the perovskite blocks. The product RbLaNb₂O₆F was then ion-exchanged with copper dichloride to yield (CuCl)LaNb₂O₆F. The synchrotron x-ray diffraction study indicates that the structure of the final compound is different from that of the pure (CuCl)LaNb₂O₇.