To obtain an efficient electrocatalyst with high conductivity and hence excellent electrocatalytic performance, nanocomposites of nickel selenide supported on cube-shaped lidless graphitic boxes (Graphitic-boxes/NiSe) are prepared as the counter electrode (CE) of quasi-solid-state dye-sensitized solar cells (QSDSSCs). In view of the extraordinary three-dimensional electron transportation pathway and high specific surface area for the cube-shaped graphitic boxes, good catalytic ability of NiSe, and their synergetic effect, the Graphitic-boxes/NiSe nanocomposite exhibits excellent electrocatalytic activity towards the reduction of I-3(-). Furthermore, the Graphitic-boxes/NiSe nanocomposite shows impressive electrochemical stability against the iodine-based electrolyte compared with NiSe and Pt. The QSDSSC with the Graphitic-boxes/NiSe CE yields power conversion efficiency of 8.26%, which is superior to the graphitic boxes CE (2.01%) and the NiSe CE (7.45%) as well, and exhibits good long-term stability. (c) 2018 Elsevier Ltd. All rights reserved.