Lung cancer is the leading cause of cancer-related mortality worldwide. Phytochemical compounds, particularly chalcones derived from Syzygium nervosum A. Cunn. ex DC., have demonstrated notable anticancer potential. The major constituent, 2′,4′-dihydroxy-6′-methoxy-3′,5′-dimethylchalcone (DMC, compound 1 ), exhibits anticancer effects against multiple cancer types. Chemical modifications of DMC, including conjugation with gallic acid (compound 2 ), have been explored to enhance its pharmacological activities. This study evaluated the gallic acid–2′,4′-dihydroxy-6′-methoxy-3′,5′-dimethylchalcone (DMC) hybrid derivative (compound 3 ) using an integrated experimental and computational workflow. In vitro 2D cytotoxicity assays demonstrated potent antiproliferative activity, with IC₅₀ values of 3.93 ± 0.47 μM in A549 and 4.88 ± 1.42 μM in non-small cell lung cancer (NSCLC) cells, while showing reduced cytotoxicity in normal fibroblasts (MRC-5; IC₅₀ = 10.48 ± 1.83 μM) compared with osimertinib. Flow cytometry confirmed a three-fold increase in apoptosis relative to controls. Pharmacological pathway analysis identified VEGFR-2 as a central regulatory node in PI3K/Akt signaling. The cytotoxic potential of compound 3 was further validated in 3D spheroid models using confocal imaging and LDH release assays. mRNA expression analysis confirmed this signaling pathway, revealing significant downregulation of PTGER4 , AKT1 , PDPK1 , and PRKCA . Molecular docking and in silico conformational analyses demonstrated strong binding affinity of compound 3 to the VEGFR-2 kinase domain, stabilizing critical active-site residues and supporting a structure-based mechanism of action. Collectively, these findings validate VEGFR-2 as a therapeutic target and highlight compound 3 as a promising scaffold for structure-based drug development against non-small cell lung cancer.