This review provides an overview of recent advances in nitrogen-containing heterocyclic molecules and their biological applications. Over 75% of drugs approved by the FDA are nitrogen-containing heterocyclic moieties, highlighting their significance in medicinal chemistry. The review covers the development of novel nitrogen-based heterocycles and their distinct biological activities over the past year (2019 to early 2020). It discusses the trends in the use of nitrogen-based moieties in drug design and the potential of these compounds in treating various diseases. The review is divided into sections focusing on four-, five-, and six-membered ring heterocycles. For four-membered rings, β-lactams are highlighted for their antibiotic properties and diverse clinical applications. Five-membered rings, including 1,2,3-triazoles, imidazoles, pyrazoles, oxadiazoles, oxazoles, isoxazoles, and thiazoles, are discussed for their broad spectrum of biological activities. Six-membered rings, such as quinolines, are also covered for their antimalarial, antibiotic, and antitubercular properties. The review details the synthesis and biological evaluation of various compounds, including their anti-inflammatory, anticancer, antiviral, antiproliferative, and α-glucosidase inhibitory activities. Structural-activity relationship (SAR) studies and molecular docking analyses are provided to explain the mechanisms of action and optimize the design of more active molecules. The review concludes by emphasizing the importance of nitrogen-containing heterocycles in drug development and their potential in treating a wide range of diseases.This review provides an overview of recent advances in nitrogen-containing heterocyclic molecules and their biological applications. Over 75% of drugs approved by the FDA are nitrogen-containing heterocyclic moieties, highlighting their significance in medicinal chemistry. The review covers the development of novel nitrogen-based heterocycles and their distinct biological activities over the past year (2019 to early 2020). It discusses the trends in the use of nitrogen-based moieties in drug design and the potential of these compounds in treating various diseases. The review is divided into sections focusing on four-, five-, and six-membered ring heterocycles. For four-membered rings, β-lactams are highlighted for their antibiotic properties and diverse clinical applications. Five-membered rings, including 1,2,3-triazoles, imidazoles, pyrazoles, oxadiazoles, oxazoles, isoxazoles, and thiazoles, are discussed for their broad spectrum of biological activities. Six-membered rings, such as quinolines, are also covered for their antimalarial, antibiotic, and antitubercular properties. The review details the synthesis and biological evaluation of various compounds, including their anti-inflammatory, anticancer, antiviral, antiproliferative, and α-glucosidase inhibitory activities. Structural-activity relationship (SAR) studies and molecular docking analyses are provided to explain the mechanisms of action and optimize the design of more active molecules. The review concludes by emphasizing the importance of nitrogen-containing heterocycles in drug development and their potential in treating a wide range of diseases.