The review highlights the origin, development, mechanistic insights and recent applications of Cu-catalyzed Sonogashira coupling reactions.

Recent developments in Glaser coupling catalysed by copper( i ) is discussed in the review with emphasis on its application.

The classical heterocoupling of a 1-haloalkyne with a terminal alkyne catalyzed by copper salts in the presence of a base for the synthesis of unsymmetrical diynes is termed the Cadiot–Chodkiewicz coupling reaction.

Nickel-catalyzed C–H activation has become a predominant and ubiquitous research area in organic chemistry.

Cobalt-catalyzed C–H activation has gone through some major advancements in the past couple of decades.

Our continuously changing environment demands sensible and sustainable chemistry. Consequently, organic synthesis started to follow green chemistry principles in recent years. It is observed that microwave (MW) radiation has been widely used as a source of energy in organic synthesis in the past decade. The MW heating approach has evolved into a new green method in organic synthesis since it provides short reaction time, high yields, and high product purities along with a decrease in the rate of by-product formation. Solvent-free reaction protocols worked well under MW irradiation. All these features make MW assisted organic synthesis an environment-friendly approach. In organic synthesis, heterocycles are vital targets especially nitrogen-containing ones because of their prominent presence in natural products and widespread applications in pharmaceutical industries. Five membered nitrogen heterocycles include pyrroles, oxazoles, pyrrolidones, etc. among which pyrroles are the most important ones due to their potent biological properties. Even though there are a variety of reaction protocols for the synthesis of pyrroles, a significant development materialized in MW assisted synthesis of pyrroles in the past few years. In this review, we focus on the developments in MW assisted synthesis of pyrroles and other five-membered nitrogen heterocycles.