Tuning Short‐wavelength Cutoff in Chalcogenide Hybrid Inorganic/Organic Polymers Glass via π‐conjugated Monomers

Visible‐opaque and near‐infrared‐transmitting (VONIRT) materials are critical for applications in forensic analysis, secure imaging, night vision, and biomedical scenarios. However, few existing materials can effectively block optical interference across the entire UV–vis spectrum. Herein, a new class of chalcogenide hybrid inorganic/organic polymers (CHIPs) is developed via multi‐monomer mechanochemical inverse vulcanization using π‐conjugated monomer (1,4‐diethynylbenzene, DEB) and dithiol monomer (1,4‐benzenedithiol, BDT). This approach enables precise tuning of the short‐wavelength cutoff from 443 to 940 nm by varying the DEB/BDT ratio. The resulting CHIPs simultaneously exhibit excellent NIR and MWIR transparency (>60%) and high refractive index ( n = 1.85–1.89). Notably, the (DEB 7 BDT 3 ) 3 S 7 CHIPs film exhibits excellent VONIRT performance, with <2% transmittance in the whole visible region (380–740 nm) and >60% in the NIR region (1.5–2.5 µm), which mainly originates from the delocalized vinyl π‐units that tailor the band structure and narrow the optical bandgap. The resulting freestanding CHIPs films exhibit excellent stability against thermal, humidity, and UV exposure, as well as strong contrast imaging capability under different wavelength illumination, rendering them suitable for pragmatic NIR imaging, information encryption, and anti‐counterfeiting. This work provides a versatile strategy for molecular‐level designing of CHIP with tunable visible‐IR selectivity for various infrared optics applications.