1：Experimental Design and Method Selection:

The PDI/GCN heterojunctions were prepared by one-step imidization reaction between PTCDA and g-C3N4 in aqueous solution.

2：Sample Selection and Data Sources:

g-C3N4 powder was prepared by thermal-induced self-polymerization of urea. PTCDA was dissolved with concentrated H2SO4 and then added into g-C3N4 colloid.

3：List of Experimental Equipment and Materials:

XRD patterns were recorded by a Japan Rigaku D/max 2000 X-ray diffractometer. UV-Vis diffuse reflectance spectra were carried out by a Cary 500 UV-Vis-NIR spectrophotometer. TEM images were recorded on a JEM-2100F high resolution transmission electron microscope. Nitrogen gas porosimetry measurement was obtained using a Micromeritics ASAP 2020 PLUS HD88 surface area and porosity analyzer. Fourier transform infrared (FT-IR) spectra were obtained on an FT-IR-8400s (Shimadzu) spectrometer. XPS was performed on a VG-ADES 400 instrument. DMPO spin-trapping EPR spectra were recorded on a JES-FA200 electron spin resonance spectrometer.

4：Experimental Procedures and Operational Workflow:

The photocatalytic performance was evaluated by the degradation of aqueous PNP and LEV over the PDI/GCN heterojunctions at ambient temperature in a self-made quartz photoreactor with the starting concentrations of PNP and LEV at 10 and 20 mg L?1, respectively. The external visible light irradiation was supplied by a PLS-SXE300 Xe lamp (300 W) with IR and 400 or 420 nm cut filters.

5：Data Analysis Methods:

The concentrations of PNP and LEV in the separated clear reaction solutions were determined on an Agilent 1260HPLC liquid chromatograph equipped with C18 column and UV detector. Concentrations of the produced organic acids and anions during the photodegradation process were determined by a Dionex DX-300 ion chromatography (IC). Chemical oxygen demand (COD) was monitored via a water quality detector (5B-3C, Lianhua, China), while total organic carbon (TOC) was determined by a Shimadzu TOC-L CPH CN200. The intermediates generated were identified by an Agilent 1200HPLC-micrOTOFESI-TOF-MS high-resolution electrospray ionization time-of-flight mass spectrometry equipped with high performance liquid chromatography (HPLC-MS).