Benzimidazole has tremendous application in medicinal chemistry and material science. The fusion of ring/substitution to benzimidazole nucleus produce polycyclic benzimidazole e. g., pyrido[1,2‐a]benzimidazole, benzimidazo[1,2‐a]quinoline, pyrrolo[1,2‐c]benzimidazolequinones (PBIs) and benzimidazo[2,1‐a]isoquinolines and these are the important synthetic strategies in drug discovery. Benzimidazole analogues have versatile therapeutic properties which encouraged the researchers to develop new therapeutic agents. Hence, the synthetic literature survey towards the polycyclic benzimidazole is paramount important. Due to the beautiful fluorescent properties of fused benzimidazole moiety, they are also used in optoelectronics, optical lasers, and organic luminophores. In addition, this scaffold has broad applications in organometallic catalysis, co‐ordination chemistry, and asymmetric catalysis. Herein, we report a vast synthetic route of benzimidazole embedded polyhetrocycles in the last eight years and their photophysical application in the modern research field.

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Herein, we report an efficient synthesis of N-substituted pyrrole derivatives and their application to construct macrocyclic oxazocinone via a two-component coupling reaction followed by base mediated intramolecular cyclization. This methodology provides an easy two-step approach to constitute a library of fused pyrrolo-oxazocinone derivatives in good yields under mild reaction conditions. The present methodology offers an easy access to the synthesis of a library of fluorescent pyrole derivatives. Among them, tert-butyl 2-(2-(3-hydroxypropyl)-7-methoxy-4,5-dihydro-2H-benzo[e]isoindol-1-yl)acetate has been employed in bio-analytical imaging which shows efficient cellular internalization along with no obvious cellular toxicity.

c‐fused furan and their derivatives are widely used as essential components of agrochemicals, bioregulators, dyes, essential skin and hair oils, cosmetics, flavouring agents, photosensitizers in industry and also show a broad range of biological activity. To the best of our knowledge, as of yet, no review has been published that covers the entire synthetic pathway leading to the formation of just c‐fused or 3, 4‐fused furans. In this review, we outline the various pathways for bicyclic, tricyclic, and polycyclic c‐fused furans, along with their detailed mechanisms, concrete examples, and biological activity. We have focused particularly on the synthetic route to medicine, natural products, and their analogues, such as c‐fused furanoditerpenes isospongiadiol, radermachol, a potential folk medicine ingredient, furo[3,4]quinolin‐4(5H)‐ones core, an inhibitor of lymphoma, bhimamycin B, hibiscone‐c core moiety of antibiotic lactonamycin, and analogue of natural product furanether A/ furanether B. Previous approaches and recent methods are described including metal‐free, transition metal, bio‐catalyst, and multi‐substrate approaches with mechanisms. The review covers the literature for more than six decades and presents an overview of the synthesis of different c‐fused furans and their utility in various disciplines such as synthetic chemistry, medicinal chemistry, and drug discovery.

Herein, we report a rare pentacyclic N‐fused hetrocycle synthesis via palladium catalyzed intramolecular C−H arylation along with the brief synthetic study of new type of bicyclic/tricyclic pyrrole rings. This pyrrole rings provided diversely substituted polycyclic nitrogen fused heterocycles from N‐benzyl/N‐benzyloxy pyrroles with good to excellent yields.