Polyheterocycles are one of the most desired synthetic targets due to their numerous and valuable applications in various fields. Multicomponent reactions (MCRs) are highly convergent one-pot processes, in which three or more reagents are combined sequentially to construct complex products, with almost all the atoms coming from the starting reagents. In this context, the syntheses of ‘heterocycles’ via MCR-based processes have been reviewed a number of times. However, there is not a single review (recent or otherwise) covering the synthesis of ‘polyheterocycles’ via a direct MCR or via a one-pot process involving MCRs coupled to further cyclizations (via ionic, metal-catalyzed, pericyclic, or free-radical-mediated cyclizations). This issue is consequently the main topic of the present review, which considers work from the last decade. The work is categorized according to the key processes involved in the syntheses of polyheterocycles, aiming to give readers an easy understanding of this MCR-based chemistry and to provide insights for further investigations. The reaction mechanisms providing novel elements to these MCR-based methods for the synthesis of polyheterocycles are also discussed.

The first bio-inspired microporous metal-organic framework (MOF) synthesized using ellagic acid, a common natural anti-oxidant and polyphenol building unit, is presented. Bi₂O(H₂O)₂(C₁₄H₂O₈)·nH₂O (SU-101) was inspired by bismuth phenolate metallodrugs, and was synthesized entirely from non-hazardous or edible reagents under ambient aqueous conditions, ena-bling simple scale-up. Reagent-grade and affordable dietary supplement-grade ellagic acid were sourced from tree bark and pomegranate hulls, respectively. Biocompatibility and colloidal stability were confirmed by in vitro assays. The material exhibits remarkable chemical stability for a bio-inspired MOF (pH = 2-14, hydrothermal conditions, heated organic solvents, biological media, SO₂ and H₂S), attributed to the strongly chelating phenolates. A total H₂S uptake of 15.95 mmol g-1 was recorded, representing one of the highest H₂S capacities for a MOF, where polysulfides are formed inside the pores of the material. Phenolic phytochemicals remain largely unexplored as linkers for MOF synthesis, opening new avenues to design stable, eco-friendly, scalable, and low-cost MOFs for diverse applications, including drug delivery.

MOFs are promising candidates for the capture of toxic gases such as SO ₂ , H ₂ S, NH ₃ and NO x . Understanding the role of different chemical functionalities, within the pores of MOFs, is the key for accomplishing superior captures of these toxic gases.

Metal–organic frameworks incorporating binuclear [Sc ₂ (μ ₂ -OH)(O ₂ CR) ₄ ] building blocks have been synthesised and characterised showing high BET surface areas and total H ₂ uptake.

MIL-53(Al) can be prepared via reaction in continuous flow in only 5–6 minutes with a space time yield of 1300 kg m⁻³ d⁻¹. Extraction of free terephthalic acid from within the pores of MIL-53(Al) using supercritical ethanol has been developed.