Acute and persistent pesticides extensively used in agricultural production, especially organophosphorus pesticides (OPPs), pose serious safety concerns to humans and ecosystems. Porous adsorbents have shown promising performance on OPPs removal from water streams, but challenges remain for integrating these materials into a continuous network with easy handling and recyclability without sacrificing their rapid and massive adsorption ability. Here, we report a monomer penetration-determined in situ synthesis methodology to create a hierarchical porous structure with wide-distributed pore size by compositing triazine-based porous organic polymers on bacterial cellulose nanofibrous aerogels. The co-existence of meso/macro/supermacropores in the composites enables superior adsorption performance by alleviating mass transfer resistance but ensuring numerous adsorption sites. Based on experimental characterizations, the as-fabricated composites exhibit integrated properties of high porosity with a wide range of pore size distribution, high surface area (391 m2/g), superior OPPs affinity, and OPP-triggered fluorescence responsibility, which are extraordinarily effective serving as adsorbents, filters, wipers, and fluorescence sensors to address OPP contaminations in the environment and food industry. The successful fabrication of such materials is expected to inspire the development of novel materials with dual-function of “decontamination-and-sensing” for a broader application.