This paper presents a review of membrane-mimetic two dimensional (2D) nanomaterials assembled from sequencedefined, diblock-like peptoids through an evaporation-induced crystallization method. Similar to those associated with cell membranes, these peptoid-based nanomembranes exhibit thicknesses in the 3.5 - 5.6 nm range, spontaneous assembly at interfaces, thickness variations in response to changes in Na+ concentrations, and the ability to self-repair. Moreover, they are highly stable, free-standing, and atomically ordered. Both experimental and simulations studies showed that these nanomembranes were formed through an anisotropic formation process. We further demonstrated the incorporation and patterning of a broad range of functional groups within peptoid membranes through large side-chain diversity and/or co-crystallization approaches. By tuning the peptoid hydrophobic domains which determine the stability of nanomembranes, we demonstrated the assembly of singlewalled crystalline nanotubes through folding peptoid-based 2D nanomaterials. Given peptoids are biocompatible and easy to synthesize, we anticipate this new class of peptoid-based 2D nanomaterials will provide a robust platform for development of biomimetic materials tailored to specific applications.