Developing　an　efficient　synthetic　approach　for　the　accurate　synthesis　of　nonprecious　metal　counter　electrode　(CE)　electrocatalysts　with　superior　catalytic　activity　and　electrochemical　stability　is　critically　important　for　the　commercial　application　of　dye-sensitized　solar　cells　(DSSCs).　In　this　study,　a　new　molecular-level　synthetic　strategy　was　innovatively　developed　by　copolymerization　of　melamine　and　resorcinol　with　formaldehyde　under　specific　pH　conditions　and　their　hydrothermal　cooperative　assembly　with　organic-inorganic　cobalt　phosphate　and　F127　to　construct　the　high-molecular-weight　EDTMPA-Co/melamine-formaldehyde-resorcinol　resin/F127　copolymer　with　good　thermal　stability　and　compositional　homogeneity.　The　subsequent　carbothermal　reduction　of　EDTMPA-Co　using　melamine-formaldehyde-resorcinol　resin　as　carbon-nitrogen　cosources　and　F127　as　a　soft　template　contributed　to　the　accurate　synthesis　of　uniformly　dispersed　cobalt　phosphide　nanoparticles　incorporated　in　a　highly　nitrogen-doped　mesoporous　carbon　(CoP/NMC)　catalyst　for　the　first　time.　It　was　found　that　the　abundant　mesopores,　high-nitrogen-content　conductive　carbon　walls　(12.8　atom　%),　and　numerous　exposed　CoP　nanoparticles　were　creatively　formed　in　the　resultant　CoP/NMC　hybrid,　which　greatly　accelerated　the　electrolyte/　electron　transportation　and　supplied　sufficient　ion-accessible　electrocatalytic　nanoactive　sites　for　catalysis.　When　applied　as　a　CE　catalyst,　the　CoP/NMC　hybrid　revealed　a　strong　synergistic　effect　in　adsorption　and　catalytic　reduction　of　triiodide　ions,　and　the　CoP/NMC　reached　a　low　charge　transfer　resistance　(R-ct)　of　1.35　Omega.　As　a　consequence,　the　CoP/NMC　CE　assembled　DSSC　delivered　a　high　photo-to-electricity　conversion　efficiency　(eta)　of　8.53%　and　exceptional　long-term　electrochemical　stability　with　a　remnant　efficiency　of　7.80%　after　200　h　of　illumination,　outperforming　the　state-of-the-art　Pt.　The　catalytic　mechanism　of　CoP/NMC　CE　toward　triiodide　reduction　was　studied　by　density　functional　theory　calculations,　which　revealed　that　the　relative　energy　for　breaking　the　I-I　bond　was　significantly　improved　by　chemisorption-induced　formation　of　Co-I　covalent　bonds　between　the　triiodide　intermediate　and　Co　sigma+　atoms　in　the　exposed　CoP　nanoactive　sites,　and　the　electrocatalytic　reduction　of　I-2*　to　I-*　was　substantially　facilitated.