4‐Methyl‐N ¹‐(3‐phenyl‐propyl)‐benzene‐1,2‐diamine (JSH‐23) is a novel chemically synthetic compound. The aromatic diamine JSH‐23 compound exhibited inhibitory effect with an IC₅₀ value of 7.1 μM on nuclear factor (NF)‐κB transcriptional activity in lipopolysaccharide (LPS)‐stimulated macrophages RAW 264.7, and interfered LPS‐induced nuclear translocation of NF‐κB without affecting IκB degradation. This mechanism of action is very rare for controlling NF‐κB activation. Furthermore, the compound inhibited not only LPS‐induced expressions of tumor necrosis factor‐α, interleukin (IL)‐1β, IL‐6 and inducible nitric oxide synthase and cyclooxygenase‐2 but also LPS‐induced apoptosis of the RAW 264.7 cells.