Cu-GTSM is a copper-containing compound and an analog of Cu-ATSM that has diverse biological activities. It is active against methicillin-sensitive and -resistant S. aureus clinical isolates (IC50s = 0.3-0.6 µM for all). Cu-GTSM inhibits the growth of SK-N-MC neuroepithelioma cells and MRC-5 fibroblasts (IC50s = 0.009 and 0.27 µM, respectively). It induces the production of reactive oxygen species (ROS) in SK-N-MC cells when used at a concentration of 5 µM. Cu-GTSM (2.5 mg/kg) reduces tumor burden in the transgenic adenocarcinoma of mouse prostate (TRAMP) model but induces weight loss and renal toxicity in the same model. Cu-GTSM-containing positron-emitting copper isotopes have been used in PET imaging applications for copper trafficking in the TASTPM transgenic mouse model of Alzheimer’s disease.