4-((Naphthalen-1-ylmethylene)-amino)-benzene Sulfonamide (NMABS) was synthesized with α-naphthaldehyde and 4-aminobenzenesulfonamide by condensation method and characterized by microanalysis, Fourier Transform Infrared (FT-IR) and Nuclear Magnetic Resonance (NMR) (1H and 13C) techniques. Thermal decomposition of NMABS was studied by Thermogravimetric Analysis/Difference Thermo Gravimetry (TG/DTG) under dynamic oxygen atmosphere at different heating rates of 10, 15 and 20 K/min-1 and decomposed into two steps as evidenced from the DTG curve. The model-free (Friedman, Kissinger-Akahira-Sunose (KAS) and Flynn-Wall-Ozawa (FWO)) and model-fitting methods (Coats-Redfern (CR)) were used to analyze non-isothermal solid-state kinetic data. Invariant kinetic parameters are consistent with the average values obtained by Friedman and KAS isoconversional methods. Each decomposition step is followed in different kinetic models, the thermal decomposition of NMABS was described by a second-order type reaction (g(α)=(1-α)-1-1 (stage 1)) and 3-D Diffusion-Jander equation (g(α)=[1-(1-α)1/3]2 (stage 2)). The positive values of ΔH# and ΔG# indicate that the decomposition process is absorption of heat and non-spontaneous nature.