Abstract: Costunolide, a natural germacranolide sesquiterpenoid, exhibits moderate anti-HCC activity. To enhance its efficacy and tumor selectivity, 37 dimeric costunolide-1,2,3-triazole conjugates were designed and synthesized through integrating dimerization and molecular hybridization strategies. An evaluation of their antiproliferative effects on HepG2, Huh-7, and SK-Hep-1 cells suggested that 25 compounds were more active than costunolide and sorafenib. The most active dimer 19 exhibited significant activity with IC₅₀ values of 1.6, 1.3, and 0.7 μmol·L⁻¹, which were 13.1, 14.2, and 34.9-fold greater than those of costunolide. Compound 19 showed favorable selectivity against human normal liver cells (THLE-2) and significantly inhibited colony formation. A combination of bioinformatics, docking, and molecular dynamics (MD) simulations identified glucose-6-phosphate dehydrogenase (G6PD) as a target of compound 19, which was confirmed by DARTS and SPR assays. Functional studies revealed that compound 19 arrested the HCC cell cycle at the G₂/M phase, suppressed migration and invasion by inhibiting epithelial-mesenchymal transition, and triggered both apoptosis and ferroptosis. These findings establish triazole-linked costunolide dimer 19 as a promising lead candidate for the development of novel anti-HCC therapies.