Freestanding ultrathin nano-membranes (FUN-membranes) are two-dimensional materials of nanoscale thickness (less than 100 nm) with little or no substrate support. Recently, there has been an emerging interest to rationally design such membranes for a broad spectrum of appealing applications ranging from lightweight, foldable electronic devices to highly efficient separation and sensing systems. In this review, we aim to summarize the recent developments of FUN-membranes fabricated via an assortment of bottom-up self-assembly strategies. In particular, we will. describe the various fabrication methods, characterization approaches, as well as the properties and applications of FUN-membrane materials. (C) 2009 Elsevier Ltd. All rights reserved.