The present invention is directed to novel inhibitors of system Xc _, also known as the cystine/glutamate antiporter. The present invention is further directed to methods of treating and detecting cancer that overexpresses system Xc _ which includes but is not limited to gliomas (including glioblastoma), triple negative breast cancer, and bladder cancer. The present invention is further directed to methods of treating seizures including epileptic seizures.
