A rapid hydrogen (H2) sensor operating at room temperature is fabricated using covalent organic framework (COF), namely Pyromellitic dianhydride and tris(4-aminophenyl)amine (PMDA-TAPA), PT COF that has a unique ability to spontaneously reduce Pd2+ into Pd0 nanoparticles without the aid of external reducing agents. The presence of surface redox sites in COF enable the rapid formation of Pd nanoparticles on COF surface under ambient conditions. The generated material, hitherto named as Pd@amicPT portrayed remarkable H2 sensing characteristics with a rare combination of high response % (67.3 ± 1) and rapid response/recovery times (5.3/3.5 s, respectively) for 1 % H2 under ambient conditions. Our results demonstrated appreciable reproducibility, repeatability, and long term stability of sensor that remained unaffected by relative humidity and a high selectivity towards H2. Further, sensor performance is found to be superior when compared to many Pd loaded 2D material based chemiresistive H2 gas sensors.