**4. Conclusions**

Layered zeolites, composed of zeolitic nanosheets linked by hydrogen bonds, provide modifiable precursors for the synthesis of novel zeolite derivatives with open pore system or large external surface area. The newly developed synthesis strategies, including the usage of delicately designed bifunctional amphiphilic SDAs and the top-down selective hydrolysis of 3D germanosilicates, have unexpectedly broken the limitation of conventional hydrothermal synthesis and largely expanded the family of layered zeolites. The successful example of layered MFI zeolite synthesized by bifunctional SDA indicated the potential of design synthesis and encouraged the researchers to explore more novel-layered zeolites. The selective degradation of germanosilicates, transforming the 3D zeolite to 2D lamellar zeolite, is highly related to the orientation distribution of instable bonds in the framework. To explore other zeolite structures besides germanosilicates with such regularity is expected to create new layered precursors.

On the other hand, several improved modification procedures have been proposed to simplify the multistep conventional processes and avoid the harsh treatment conditions. The variation of post-synthesis modifications is potential in providing more derivatives for the layered precursors, showing the infinite possibilities of the modifiable 2D layered zeolites.
