How to efficiently control the metal sites in carriers is of great importance in the design of high-efficiency heterogeneous catalysts, but still remains to be difficult. Herein, we provide an efficient one-pot strategy to design conjugated microporous polymers (CMPs) loaded with superfine palladium (Pd) sites, referring a Pd-catalyzed Suzuki coupling reaction and pyrolysis reduction process. Beneficial from micropore-confinement effect by CMPs, the size of deposited Pd can be well controlled (lower than 2?nm), exhibiting excellent catalytic activity on p-nitrophenol reduction. Super small size of Pd sites and the retainment of pores during the Pd formation is thought to be the main reason for high catalytic activity of the Pd/CMPs catalysts. It expands the exploration and development of heterogeneous catalysts by micropore-confined strategy. (C) 2019 Elsevier Inc. All rights reserved.