Catalytic gas sensor technology, invented in 1926, is recorded to be the first modern age gas detection system that possesses significant advantages, including affordable, insensitive to humidity, and appreciable reproducibility. [10][11][12] Alongside, the system has certain drawbacks like poor sensing performance and the employed solid-state catalyst are highly poisonous that has the potential to cause severe health concerns when it comes in contact with the users. [10,13] This was followed by electrochemical gas sensors that are commercially available to sense a wide range of gases. [14,10,15,16] This technology has gained increased attention in a short period due to easy tunability of diffusion barriers on the surface of the porous membrane, [17] but poor chemical stability drastically declines its long-term durability. [18] Similarly, metal oxide semiconductor (MOS) sensors achieve high sensing performance only when operated at elevated temperatures that, in turn, requires more operating power. [19][20][21] Given this, it is vital to develop room-temperature operating, low cost, and compact gas sensors with excellent sensing performance and ambient stability. [22,23] Porous organic materials have been used in multiple applications to date. [22,24] One of the porous and multifaceted functional groups in chemistry are hydrazones; these systems can be found in various chemical structures that are being used for a plethora of different technological applications. The diverse behavior of hydrazone arises due to the presence of azomethine (CNN) group, which makes it useful in various fields. [25] A close study of hydrazone structure has revealed that the hydrazone functional group possesses some of the unusual properties such as an exhibition of both electrophilic as well as nucleophilic behavior, the existence of acidic proton on the nitrogen, conformational isomerism at CN bond, etc. [26,27] One crucial member of this hydrazone family is tris(ketohydrazone), a tautomeric structure, first realized by Lee et al., [28] in the early 2000s. These systems, due to their dynamic architecture, are uniquely placed in the hydrazone family. Literature studies have revealed that these systems are capable of undergoing keto-hydrazone tautomerism readily. Due to the presence of their extensive cage-like structures coupled with the electronic properties such as acidity, nucleophilicity, etc. they are highly sought after candidates for different sensing applications. [29,30]
