Membraackackackne fabrication, permeability testing and transport analysis of 2DPA-1 was supported by the Center for Enhanced Nanofluidic Transport (CENT), an Energy Frontier Research Center sponsored by the US Department of Energy (DOE), Office of Science, Basic Energy Sciences under award #DE-SC0019112. The synthetic chemistry and mechanical testing aspects of this work were funded by the Army Research Laboratory under cooperative agreement W911NF-18-2-0055. H.J.K. holds a Career Award at the Scientific Interface from the Burroughs Wellcome Fund, which supported the molecular modelling aspects of this work. We acknowledge fabrication support from the Center for Nanoscale Systems at Harvard, a member of the National Nanotechnology Coordinated Infrastructure Network (NNCI), which is supported by the National Science Foundation under NSF award no. 1541959. This research used beamline 11-BM Complex Materials Scattering (CMS) of the National Synchrotron Light Source II (NSLS-II) and the Center for Functional Nanomaterials (CFN), both of which are US DOE Office of Science User Facilities operated for the DOE Office of Science by Brookhaven National Laboratory under contract no. DE-SC0012704. We thank E. Tsai for her assistance in performing experiments at the beamline, R. Verduzco for beamline access, A. Penn and E. Brignole for MIT.Nano assistance for STEM and Cryo EM, and S. Xin Li for discussions on 2D membrane properties. We acknowledge MIT.Nano facilities and the Cypher VRS DURIP award (N000142012203) for the support on AFM characterizations. M.K. acknowledges support by the German Research Foundation (DFG) Research Fellowship KU 3952/1-1.