Molecular sieving metal organic frameworks (MOFs) membranes offer great potential for gas separation in terms of their low energy consumption. This thesis aims to develop novel and facile methods to fabricate high performance MOF membranes for energy efficient gas separation. Membranes constructed from two dimensional (2D) layered MOFs can be ultrathin, thus enabling the minimization of transport resistance, whilst, maximizing permeability. This thesis demonstrates the synthesis of novel 2D materials/MOF hybrid nanosheets successfully. Utilizing these 2D hybrid nanosheets as building blocks, facile and advanced fabrication strategies were developed for ultrathin molecular sieving MOF-based membranes.