This review summarizes the recent developments in using QMAs in several regioselective transformations, including allylic substitution, multicomponent reactions, deoxyacylation, Wittig reaction, deuteration, aryloxylation, and [3+2] annulations. The review demonstrates that the production of C-C, C-X, C-P, and C-O bonds has significantly advanced with the invention of metal-free, cheap, and scalable techniques employing QMA as a starting material.

Catalysts play a vital role in various chemical industries. Homogeneous and heterogeneous catalysts have their specific advantages and disadvantages in terms of the tradeoff between efficiency and recyclability. Nanocatalysts can provide high efficiency as they operate practically in a homogeneous mode, but the recyclability remains a challenge. The concept of ‘dip catalysts’ was developed in this context; the nanocatalyst embedded within a swellable polymer matrix can effectively harmonize the advantages of homo and heterogeneous catalysts. A dip catalyst can be physically inserted in a reaction system to start the catalytic reaction, and retrieved to stop the reaction. By careful optimization of the nanocatalyst-polymer composition, the catalyst leaching can be prevented and the dip catalyst used in innumerable cycles. The dip catalyst can be monitored through the usage cycles using appropriate microscopy and spectroscopy tools, in order to assess the fate of the catalyst within. Since the discovery of this mode of catalysis, several applications have emerged in the literature. This article provides a brief overview of the concept of dip catalysts, their application and evolution.

Photocatalytic solar fuel production has emerged as a sustainable route for converting abundant solar energy into storable chemical fuels. Key processes include water splitting for H₂ generation, CO2 reduction to value-added hydrocarbons, and N2 fixation to NH3, offering solutions for both energy and industrial decarbonization. Recent progress in band structure engineering, heterojunction design, single-atom catalysis, and defect/strain modulation has improved light harvesting, charge carrier separation, and catalytic activity. However, challenges remain in achieving high solar-to-fuel efficiencies, product selectivity, stability, and scalability under practical conditions. Here, we will discuss recent advances, existing challenges, and future opportunities in photocatalytic solar fuel production, with a focus on H2 generation, CO2 reduction, and NH3 fixation.