A study was conducted to investigate structural characterization of ternary Cu2MoS4 nanosheets during solvothermal synthesis at the atomic level. A solution was used for conducting the investigations in which Cu2O nanocrystals were the sacrificial Template and the structure of the as-obtained Cu2MoS4 was investigated at the atomic level using atomic-resolution electron microscopy, synchrotron-radiation-based X-ray absorption fine-structure spectroscopy (SR-XAFS), and powder-diffraction-based Rietveld refinement techniques. The growth mechanism was also investigated using time-dependent experiments. Additional experimental results indicated that Cu2MoS4 nanosheets were potential photocatalysts at visible wavelengths and electrocatalysts for the hydrogen evolution reaction (HER).