The development of modern society stimulates the adjustment of multifunctional nanoscale materials.In this contribution,two constituent-tunable metallophthalocyanine covalent organic polymers(MPc-COPs)covalently functionalized graphene oxide(GO-PcP 1 and GO-PcP 2)were rationally designed and fabricated for optoelectronics and electrocatalysis(Figure 1).The resultant GO-PcP nanohybrids exhibit markedly enhanced nonlinear optical and optical limiting performances over those of their components and physical mixtures at 532 nm in the nanosecond pulse range,and the optical nonlinearity can be further optimized by tuning the linkage type between the four-branched tetra-amine metallophthalocyanine units.The hydrogen evolution reaction catalytic performance is investigated by the linear sweep voltammetry in the presence of 0.5 M H2SO4 aqueous solution.Under optimal conditions,the overpotential to reach 1 mA cm-2 is measured to be 237 and 210 mV for GO-PcP 1 and GO-PcP 2,respectively,which places GO-PcP 2 among the best metallophthalocyanine polymers-based HER catalysts reported in the literature.The improved performances are ascribed to the positive synergistic effects between MPc-COPs and GO.To the best our knowledge,the MPc-COPs covalently functionalized graphene oxide as a bifunctional system for efficient optical nonlinearity and electrocatalysis has not been reported.Notably,this present study introduces a new strategy for precision preparation of MPc-COPs based nanomaterials and exploring their applications to develop highly efficient optical limiters and electrocatalysts.