Covalent organic frameworks (COFs) are attractive for chemical sensing applications because their structures contain delocalized π electrons and active sites that are evenly distributed. COF-based chemical sensors are largely restricted to luminescence and absorption-based mechanisms of sensing. The present study demonstrates the potentiality of exfoliated COF nanosheets hybridized with palladium nanoparticles (Pd NPs) for effective chemiresistive H2 sensing, for the first time. The hybridization of Pd NPs with the nanosheets of an imine-based covalent organic framework (ePd@TpPa-SO3H COF) has turned an innocent bulk COF into an effective chemiresistive H2 sensor.