The resurgence of interest in sodium-ion batteries (SIBs) is largely driven by their natural abundance and favorable cost, apart from their comparable electrochemical performance when compared with lithium-ion batteries (LIBs). The uneven geographic distribution of the raw materials required for LIBs has also contributed to this. The solid-state electrolyte (SSE) is typically one of the vital components for energy storage in SIBs and for achieving high electrochemical performances. SSEs are preferred over liquid electrolytes primarily for enhanced safety and stability, apart from the option of accessing higher energy density. A single sodium-ion selective conductor minimizes dendrite formation and cell polarisation, among many other benefits over binary ionic conductors in battery operation. Here, we demonstrate the first example of a sulfonated supramolecular organic two-dimensional (2D) nanosheet as a novel class of single sodium-ion conductors prepared from the self-assembly of a functionalized guanidinium ion (AD-1). Solvent-assisted exfoliation of the bulk powder in water yielded nanosheet morphology, whereas nanotube morphology was achieved in isopropanol (IPA). In contrast, self-assembly with systematic water/IPA solvent ratio variations produced marigold, sunflower, and nanorod morphologies. Thermodynamic parameters, crystallinity, elemental composition, and varying natures of hydrogen bonding in five distinct morphologies were determined using microscopic and spectroscopic studies. The single Na+ conducting property for the respective morphology is correlated in terms of morphology, crystallinity, and the solvent used to achieve the specific morphology. Importantly, with high crystallinity with directional ion channels, 2D nanosheet morphology exhibits the highest single Na+-ion conductivity of 3.72 × 10-4 S cm−1 with activation energy 0.28 eV showing moderately high Na+-ion transference number of 0.83 at room temperature without incorporating any additional sodium salts and organic solvents. This report is believed to be the first to show the significance of nanostructure morphologies in attaining a high single-Na+-ion transport phenomenon.