<p>n-Butanol is one of the most well-known flammable and hazardous compounds that pose risks to both human health and safety. Thus, monitoring its concentration in the environment is critical. The demand for efficient toxic gas detection systems has driven advancements in gas sensor technology. Molybdenum diselenide (MoSe₂) has garnered significant attention owing to its ability to detect gases at room temperature. In this study, we present a novel sensor based on biofunctionalized magnetic nanoparticles integrated with MoSe₂ for detecting n-butanol. Biofunctionalized magnetite (CT-Fe₃O₃) was prepared using leaf extract obtained from <i>Cinnamomum tamala</i> and subsequently incorporated into a MoSe₂-based nanocomposite via a hydrothermal synthesis approach. The resulting MoSe₂-CT-Fe₃O₃ nanocomposite was employed to fabricate gas sensors and tested for n-butanol detection at various concentrations. The sensor demonstrated notable performance, achieving a response (ΔR/Rair %) of 47% for 5&#xa0;ppm of n-butanol, highlighting its potential for room-temperature gas sensing applications.</p> Graphical Abstract <p></p>