The active pharmaceutical ingredient 2-chloro-5-nitrobenzoic acid (2Cl5NB) is an antiviral agent for immunodeficiency diseases, including the human immunodeficiency virus (HIV) infection [1]. Taking into account today pharmaceutical industrial challenges, the goal of this study was to obtain and characterize new 2Cl5NB molecular salts based on pharmaceutical active monoethanolamine (MEA) anion. MEA is a naturally occurring component, used as base chemical in the production of pharmaceuticals and recently as therapeutic agent in the treatment of age-associated human diseases [2]. Herein, we present a comparative study of crystal structures, thermal stability, decomposition, kinetics and luminescent properties of two different molecular salts monoethanolammonium 2-chloro-5-nitrobenzoate (1) and N-(1,1- dimethyl-3-oxobutyl)monoethanolammonium 2-chloro-5-nitrobenzoate (2), obtained by different reaction mechanisms of 2Cl5NB with MEA, in diethylether, respectively acetone. The crystal structure determination reveals that compound 1 crystallizes in triclinic P-1 (№2) space group [3], while 2 in monoclinic P21/c (№14) space group: a=9.0876(6), b=26.7814(14), c=7.1888(5) Å, β=93.342(6)°, V= 1746.62 Å3 and both compounds are dominated by charge-assisted O–H···O– and N+ –H···O– hydrogen bonds. Thermal analysis exhibits similar melting points at ~ 120°C and an improved thermal stability for compound 2 compared to 1. In addition, a kinetic study under nonisothermal conditions was performed, using three different methods KissingerAkahira-Sunose (KAS), Friedman (FR), and nonparametric kinetics method (NPK).figureFigure 1. View of asymmetric units and thermoanalytical curves of 1 (a) and 2 (b) Figure 2. Thermal analysis for compounds 1 (red) and 2 (blue).