Air pollution could harm humans and pose a lifelong threat to the health of every individual. The detection of these pollutants has a significant impact on the lives of tens of thousands of people and all living creatures on earth. Regarding this objective, metal-organic framework (MOF)-based sensors and biosensors play a crucial role in identifying these hazardous substances. Important modified nanomaterials consisting of these sensors are required because the specifics and characteristics of these devices depend entirely on the type of materials employed. The current review explains MOFs in terms of their definition, structural characteristics, various types, synthetic routes, and significant use in toxic gas sensing assays. MOFs as porous compounds with clusters or ions, as well as some ligands attached to these clusters, have attracted considerable interest. Additionally, recent advances in the characteristics and physio-chemical properties of MOFs, as well as their functional applications in the development of electrochemical and optical sensing assays via various recognition elements for the detection of various toxic gases, are thoroughly discussed. Finally, the limitations of the current advances, including future obstacles to the successful development of sensing techniques employing functionalized MOFs, are addressed.