Ta-based compounds show Pt-like behavior: Binary tantalum compounds as counter electrodes (CEs) in dye-sensitized solar cells (DSCs) demonstrate Pt-like electrocatalytic activity and competitive photovoltaic performance, matching the performance of DSCs with Pt CEs. The first-principle density functional theory (DFT) calculations provide a strategy for understanding the relationship between the electronic structure and the catalytic activity of CE catalysts in DSCs.