Zr-MOFs play pivotal roles in water environmental chemistry, owing to the exceptional resistance against hydrolysis. But most Zr-MOFs mainly absorb ultraviolet light, which limits their widespread applications. Here, an entirely novel Zr-MOF was elaborately designed and fabricated. This Zr-MOF performs excellent photoluminescence and highly selective fluorescence quenching sensing abilities towards Cr2O72- and CrO42- ions, even in the presence of other single or mixed anions/cations. Notably, its fairly low detection limits (DL) were determined to be 3.98 and 5.82 ppb, providing rather high fluorescence quenching constant (Ksv) values of 4.32 × 104 and 2.23 × 104 M-1, and quantitative detection capability, respectively. Competitively absorbing excitation light energy and coordinating with Zr-MOF by Cr(VI) were rigorously validated as the potential fluorescence quenching mechanism. Moreover, the inherent optical-electronic properties endow it with considerable photochemical decolorization talent for reactive dye RB13 under UV light. To further polish its band state, novel heterojunction materials In2S3/Zr-MOF (labeled as M3, M5 and M7) were then fabricated. Under low-energy xenon lamp irradiation, M3 can reduce Cr(VI) by 98.4% within 60 min, affording a pretty high reaction rate constant of 0.069 min-1, which was confirmed to be 2.3 and 12.7 times of bare In2S3 and Zr-MOF, respectively. And the decontamination efficiency of M5 for RB13 was calculated to be 97.42%, with the reaction rate constant of 15.6 and 36.8 times of pristine In2S3 and Zr-MOF. By virtue of free radical trapping experiments and EPR test, combined with the electron flow direction analyzed by XPS, In2S3/Zr-MOF was confirmed to be typical type-II heterojunction. This study donates a feasible way to overcome the limitations of Zr-MOFs platforms and offers an innovative concept to design novel bi-functional water environment monitoring and remediation materials.