The compounds herein disclosed are tetrahydroisoquinoline analogs that have modifications on the phenyl rings by introducing groups with various electronic properties. These derivatives of tetrahydroisoquinoline have been shown to have anti-proliferative activity against cells. In particular, the compounds have been found to be effective in inhibiting the proliferation of cancer cells, such as cancer cells that originated in breast tissue. Additionally, it has been shown that the novel compounds have IC50 values against the breast cancer cells that are 6-10-fold less than the IC50 of tamoxifen.