**1. Introduction**

An online search reveals that C3N2H4 is the formula for the chemical molecule imidazole. A solid that is either colorless or white and water-soluble only slightly produces an alkaline solution. It is a diazole and an aromatic heterocycle in a chemical sense since it has meta-substituted nitrogen atoms that are not contiguous. Imidazole was named in 1887 by the German chemist Arthur Rudolf Hantzsch (1857–1935) [1].

Because of their ability to fluoresce and glow under certain conditions, imidazoles are widely used in analytical processes [2]. The noticeable alteration in fluorescence following metal binding is a crucial characteristic that makes imidazole derivatives more desirable as a chelator [3]. As a result, extremely sensitive fluorescent

chemisensors for sensing and imaging metal ions have been built using imidazole derivatives [4]. Its chelates, especially those that include Ir3<sup>+</sup> , are crucial parts of organic light-emitting diodes and are excellent candidates for fluorescent chemisensors for metal ions [5].

Chemical compounds with an imidazole ring system have many pharmacological properties and play indispensable roles in biochemical processes [6]. Lots of the substituted imidazoles are known as inhibitors of fungicides and herbicides, plant growth regulators, and therapeutic agents. Modern advancements in green chemistry and organometallic chemistry have broadened the limit of imidazoles to the synthesis and application of a prominent category of imidazoles as ionic liquids and imidazole-associated N-heterocyclic carbenes. Imidazole derivatives are also applied as possible anticancer agents. Lately, heterocyclic imidazole derivatives have drawn attention due to their unique optical properties. These compounds play a particularly substantial part in chemistry as mediators for synthetic reactions and the development of functionalized materials. The amino acid histidine, vitamin B12, a component of DNA base structure, purines, histamine, and biotin are just a few examples of well-known components of human bodies that contain the imidazole core. Other examples include azomycin, cimetidine, and metronidazole [7]. The use of imidazole-based compounds was reported for multidrugresistant tuberculosis, antifungal and antimycobacterial activity, and bactericidal effects [8].

The most essential technique for determining the relative atomic locations in a molecule structure is X-ray diffraction. Additionally, it can offer objective proof of the dimensions and geometry of molecules. The stability of a structure is aided by hydrogen bonds. As a result, it is a component of molecular conformation in that symmetry, and the subsequent arrangement of the molecules should result in the production of as many hydrogen bonds as feasible [9]. This chapter describes the author's work on the synthesis and crystal structure determination of a few significant novel imidazole derivatives.
