Thirty-eight 5-arylidene-2(5H)-furanone derivatives possessing halo-, methoxy-, oxo-, dioxo-, and thiophenyl groups as well as anthraquinone and naphthquinone moieties were synthesized, and their cytotoxicity was evaluated against various cancer cell lines. The introduction of halogen atoms or nitro group at aromatic ring of 5-arylidene-2(5H)-furanone was shown to increase the cytotoxicity with 5-(3-nitrobenzylidene)-2(5H)-furanone (21) being the most potent. Among anthracenyl or naphthalenyl derivatives, (E)-5-[2-(1,4-dimethoxy-9,10-dioxo) anthracenyl]-2(5H)-furanone (34) showed the most potent cytotoxic activity.