Cost-effective monitoring of contaminants of emerging concern (CECs) and persistent organic pollutants (POPs) is essential for environmental quality management worldwide. This study focused on the development, and validation of novel and cost-effective passive samplers for monitoring time-weighted average concentrations (TWACs) of a wide array of pharmaceuticals and pesticides. Five distinct sorbent materials were examined, comprising three self-developed Smart Sponges, namely A-SS, B-SS, and CS, and commercially available pen tips and hydrophilic-lipophilic-balanced (HLB) materials. These materials were subjected to exposure to 80 model chemicals, reflecting diverse characteristics such as a wide range of log K_ow (-2.60–7.02), pK_a (0.62–14), molecular weights (129.16–747.9 g/mol), and a variety of functional groups. Results of laboratory experiments revealed the superior performance of the A-SS sorbent in capturing 45 target analytes with diverse physicochemical properties, surpassing the effectiveness of other tested materials based on seven criteria. Further tests confirmed that the A-SS sorbent demonstrated consistent performance across varying pH, salinity, and temperature conditions, showcasing its robustness for application in fluctuating aquatic environments. Field validation of A-SS samplers was conducted in 31 locations in Hong Kong’s rivers and estuaries. The overall linear relationship between TWACs of the target contaminants in the A-SS samplers and their concentrations in grab water samples using the pooled regression analysis (chemical-site pair) showed the following results: pharmaceuticals: R² = 0.636, F_1,299 = 524.17, p < 0.001; pesticides: R² = 0.583, F_1,311 = 434.93, p < 0.001. Compared to previously developed passive samplers, the production cost of this Smart Sponge passive sampler is only US$2 per gram, thereby substantially reducing monitoring costs and enabling more frequent monitoring of CECs and POPs worldwide, with environmental stability and friendliness.