Single agents against multiple drug targets are of increasing interest. Hormone-dependent breast cancer (HDBC) may be more effectively treated by dual inhibition of aromatase and steroid sulfatase (STS). The aromatase inhibitory pharmacophore was thus introduced into a known biphenyl STS inhibitor to give a series of novel dual aromatase− sulfatase inhibitors (DASIs). Several compounds are good aromatase or STS inhibitors and DASI 20 (IC50: ...