An intriguing functional supramolecular Tb(III)-metallogel (Tb-OX) is derived through the sonication of terbium(III) chloride hexahydrate and oxalic acid dihydrate in N,N-dimethylformamide (DMF) solvent under ambient conditions. A rheological investigation proves the mechanical stability of the supramolecular Tb-OX metallogel. Field emission scanning electron microscopy (FESEM) microstructural analysis unveils the rocklike morphological pattern of the Tb-OX metallogel having a supramolecular network. Metallogel synthesis, crystallinity, and thermal behavior of Tb-OX are evaluated with the help of IR spectroscopic investigations, powder X-ray diffraction (PXRD), and thermogravimetric analysis (TGA). Exhaustive investigations and analyses of the optical and electrical parameters of Tb-OX establish the semiconducting properties of the Tb-OX metallogel. Based on its conducting properties, the Tb(III)metallogel is successfully applied to a metal-semiconductor junction-based photosensitive Schottky barrier diode device with excellent charge transport properties.