During the past few decades, cholesteric liquid crystals (CLCs) with intrinsic helical configuration of molecular directors have great perspectives towards a wide range of advanced photonic applications such as brightness-enhancement devices of liquid crystal (LC) displays, diffractive optical elements, smart windows, mirrorless lasers, and sensors[1–5]. Thanks to the Bragg reflection of CLCs, which confers nontrivial optical functionalities, significant structural color can be generated to reflect circularly polarized (CP) light with identical handedness in the visible spectrum. In general, the colors of CLCs, exhibited by the selective reflection wavelength, depend on the helical pitch length () or/and the average refractive index (average RI, )[6–8] in response to the external stimuli, such as temperature, electric field, and light irradiation. Also, some organic compounds can be incorporated into CLCs to alter the optical properties directly. The molecular structure of CLCs can be further modified with recognition fragments and utilized to absorb specific analytes. The uptake of specific analytes will affect and and reveal different reflected colors consequently[9–11]. This feature is beneficial for the detection of volatile samples such as alcohol, amine, and acetone[12–14], providing a versatile sensing platform with several advantages like low cost, being power-free, and naked-eye detection.