Breast cancer is the primary cause of cancer deaths globally and the second most common cancer in women after skin cancer. There are a number of core strategies for treating cancer including surgery, radiation therapy, immunologic therapy, and chemical-based therapies. Usually, a combination of these techniques is employed, and the majority of therapeutic strategies have a chemical component. Estrogen receptor antagonists or selective estrogen receptor modulators have a very high survival rate in treating patients with breast cancer, but they do have a chemoresistance, that why science in a bad need for investigating new antiestrogens with low or no drug resistance. Estrogen receptor alpha (ERα) is expressed in nearly 70% of invasive breast cancers. ERα is a steroid hormone receptor and a transcription factor, when activated by estrogen, activates oncogenic growth pathways. Estrogens control multiple functions in hormone-responsive breast cancer cells, and ERα plays a major role in the etiology of the disease, serving as a major prognostic marker and therapeutic target in breast cancer management.