Twenty scopoletin derivatives were developed by a systematic combinatorial chemical approach and their chemical structures were confirmed by MS, IR, 1H NMR spectra and elemental analysis. Primary screening against mammary (MCF-7 and MDA-MB 231) and colon (HT-29) carcinoma cells indicated that five compounds (8d, 8g, 8j, 11b and 11g) displayed high antitumor potencies with IC50 values below 20μM whereas scopoletin ...