Complex　nanostructures　with　distinct　spatial　architectures　and　more　active　sites　hold　broad　prospects　in　new　energy　conversion　fields.　Herein,　a　facile　strategy　was　carried　out　to　construct　triple-shelled　Co-VSex　nanocages,　starting　with　an　ion-exchange　process　between　Co-based　zeolitic　imidazolate　framework-67　(ZIF-67)　nanopolyhedrons　and　VO3-　followed　by　the　formation　of　triple-shelled　Co-VSex　hollow　nanocages　during　the　process　of　increasing　the　solvothermal　temperature　under　the　assistance　of　SeO32-.　Meanwhile,　triple-shelled　Co-VSx　and　yolk-double　shell　Co-VOx　nanocages　were　fabricated　as　references　by　a　similar　process.　Benefiting　from　the　larger　surface　areas　and　more　electrolyte　adsorption　sites,　the　triple-shelled　Co-VSex　nanocages　exhibited　excellent　electrocatalytic　performances　when　applied　as　the　electrochemical　catalysts　for　dye-sensitized　solar　cells　(DSSC)　and　hydrogen　evolution　reactions　(HER).　More　concretely,　the　DSSC　based　on　the　Co-VSex　counter　electrode　showed　outstanding　power　conversion　efficiency　of　9.68%　when　its　Pt　counterpart　was　8.46%.　Moreover,　the　Co-VSex　electrocatalyst　exhibited　prominent　HER　performance　with　a　low　onset　overpotential　of　40　mV　and　a　small　Tafel　slope　of　39.1　mV　dec-1　in　an　acidic　solution.　Copyright　©　2019　American　Chemical　Society.