Carbon dots (CDs) due to their excellent photostability, good biocompatibility and multicolor fluorescence, have been preferentially selected as luminescent fluorophores and co-assembled with various chiral host templates in recent years. The as-prepared composites exhibit marvellous circularly polarized luminescence (CPL) activity and show promising potentials in the fields of stereopsis and optoelectronic display, which have drawn increasing attention. However, the fussy assembly procedure and over-reliance on template chirality extremely limit the design and application of CDs-composited materials in the field of CPL. In this work, we directly prepared the CDs-composited G-quartet hydrogels with CPL activity using a one-step microwave-assisted method, and their helical chiral structure and CPL orientation can be arbitrarily switched back and forth between left-handed and right-handed through K+ and formation kinetics. Finally, the CDs-composited G-quartet hydrogels can be applied in anti-counterfeiting printing for encrypted information transfer, and their outstanding thermal cycling stability and CPL dissymmetry factor (g lum) of up to 10−1 demonstrate a wider application potential in CPL active materials based on CDs. [Display omitted] • CDs-composited fluorescent G-quartet hydrogels were directly prepared by a simple one-step microwave method. • Helical chirality and CPL properties of hydrogels can be flexibly regulated by metal ions—K+ and formation kinetics. • The CPL dissymmetry factor (g lum) of hydrogels reached 10−1, which is much higher than that of most CPL materials. • The CDs-composited G-quartet hydrogels can be employed in anti-counterfeiting printing for information encryption. [ABSTRACT FROM AUTHOR]