CrystEL is a project founded by the joint call of the Fondazione CARIPLO and Regione Lombarda for an incremented attractivity and competitiveness of the regional research system in the ERC framework.The project consists in the synsthesis and characterization extended single two-dimensional (2D) crystals suitable for hosting a quantum spin Hall insulator (QSHI) state. These 2D crystals belong to two different classes of materials, the Xenes, namely elementary 2D lattices such as silicene, germanene, and stanene, and transition metal dichalcogenides (TMDs) in the distorted octahedric phase (1T'). Among the Xenes, stanene is the target material. Stanene will be epitaxially grown on ad hoc substrates. Extende TMD layers including MoS2 and WS2,will be grown in the trigonal prismatic phase (2H) on inert substrates by means of chemical vapour deposition (CVD). Transition to the 1T' phase will be achieved via electron transfer. The final goal os to develop a platform of 2D materials where to verify a QSHI state.