A gas membrane separation/array fluorescence visualization (GMS/AFV) device is developed by integrating hydrazine-based carbonized copolymer dots (PD-N 2 H 4 ) for visual on-site analysis. The novel PD-N 2 H 4 was synthesized using a "polymer template" approach, exhibiting strong blue fluorescence capable of visual sensing. The GMS/AFV device integrates sample preparation and detection all-in-one, consisting of a smartphone, a sample pretreatment system, and an optical system. In the detection procedure, the samples will be treated in the sample pretreatment system to create volatile gases. Therefore, any gas samples as well as solid and liquid samples that potentially produce volatile gases can be visually detected on-site by the device. H 2 S was utilized as a model analyte to test the practicality of the GMS/AFV device. The entire analysis can be finished in 3 min, and the limit of detection of H 2 S is as low as 3.4 μg/L. Surprisingly, the device is also capable of high-throughput sample detection, which can process 48 samples simultaneously in about 20 min. The device offers a quick, easy, cheap, and environmentally friendly way to analyze volatile gases, and it creates new opportunities for on-site detection of complex samples.