A cell-permeable dimeric copper complex that competitively binds β-catenin and disrupts β-catenin/Tcf4 interaction reversibly (IC50 = 5.0 µM), and acts as a Wnt signaling inhibitor. Shown to induce preferential growth arrest in β-catenin overexpressing HCT116 colon cancer and HEK293 cells (≤ 10 µM), and downregulate mRNA expressions of c-Myc and cyclin D1. Reported to inhibit PP2C and proteasomal activities at higher concentrations (~50 µM).