The crystal structures of two pyrazole derivatives, C5H10N4O2 (1), which is a neutral species and C8H12N6O3S (2), a nitrate salt, have been determined from single crystal X-ray analysis and their electronic structures were calculated at the DFT level with a detailed analysis of Hirshfeld surfaces and fingerprint plots facilitating a comparison of intermolecular interactions in building different supramolecular architectures. Investigation of intermolecular interactions and crystal packing via Hirshfeld surface analysis reveals that the close contacts are associated with weak interactions and the fingerprint plots demonstrate these weak interactions. The large HOMO-LUMO energy gap indicates a high kinetic stability of both the compounds in their electron transfer. (C) 2011 Elsevier B. V. All rights reserved.