Finding new protic ionic liquids (PILs) of pharmaceutical agents for the treatment of main infectious killing diseases attracted broad interest in recent years. 4-Nitrobenzoic acid (4NBH) has been recently listed as a promising new agent for the treatment of tuberculosis, showing a selective inhibition of Mycobacterium tuberculosis species [1]. Herein, we expand the world of 4NBH salts [2], presenting two new alkanolammonium PILs with melting points below 100ºC obtained from interaction of diethylethanolamine (DEEA) with 4NBH: HDEEA-4NB (1) and HDEEA-4NB-4NBH (2). This study reveals for the first time the X-ray single-crystal structure, thermal stability, degradation and luminescence properties of diethylethanolammonium PILs. Both compounds crystallize in triclinic P-1 (№2) space group, analysis of supramolecular architectures indicating that intermolecular interactions are formed between protonated HDEEA and deprotonated 4NB in compound 1 and protonated and deprotonated acid in 2. Crystal packings of both compounds are dominated by charge-assisted N+ –H···O– and normal O–H···O hydrogen bondes, and π∙∙∙π stacking interactions (about 3.84 Å) between aromatic rings of deprotonated 4NB (Fig. 1). Calorimetric and thermogravimetric data confirm the absence of solvent in studied compounds (Fig. 2). The luminescence intensity of 2 is more than seven times magnitude higher than 1 and free acidfigureFig.1 Reprezentation of non-covalent interactions in 1 (a) and 2 (b) Fig.2 Thermoanalytical curves of compounds (1 - blue) and (2 -black).