<p>Single crystals of 3-carboxyanilinium nitrate (3-CAN) were synthesized and characterized using differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), FTIR spectroscopy, single-crystal X-ray diffraction, and computational analysis. DSC measurements indicate that 3-CAN does not undergo an isotropic melting transition but instead exhibits exothermic decomposition at 493&#xa0;K with an enthalpy change of 979.7&#xa0;J&#xa0;g⁻¹. TGA analysis further confirmed that the exothermic DSC event corresponds to thermal decomposition accompanied by major mass loss. Single-crystal X-ray diffraction reveals that 3-CAN crystallizes in the monoclinic space group C2/c, forming alternating organic and inorganic layers interconnected by extensive charge-assisted N–H···O hydrogen bonds. The 3-carboxyanilinium cations further assemble into cyclic carboxylic acid dimers through strong O–H···O interactions. Hirshfeld surface analysis shows that O···H/H···O contacts contribute 49.6% of the total intermolecular interactions, confirming the dominant role of hydrogen bonding in crystal stabilization. FTIR spectroscopy reveals pronounced modifications in inter- and intramolecular hydrogen-bonding environments upon salt formation, consistent with the observed crystal architecture. Overall, the combined crystallographic, thermal, spectroscopic, and theoretical approach demonstrates that charge-assisted hydrogen bonding and electrostatic interactions govern the stabilization of the 3-carboxyanilinium nitrate crystal structure.</p> Graphical abstract <p>Graphical abstract illustrating the synthesis of 3-CAN crystals and their structural, thermal, vibrational, and computational characterization, highlighting dominant hydrogen-bonding interactions and electrostatic stabilization.</p>