The purpose of this reprint is to introduce the reader to the latest advances in the chemistry of N-heterocycles, such as the synthesis, reactivity, and applications of aromatic and saturated nitrogen heterocyclic compounds. The role of N-heterocycles in human life is difficult to overestimate; their diverse application spans from the pharmaceutical industry to the production of energetic materials, dyes, and non-linear optical materials, among many other areas. With this reprint, we aim to highlight the most recent and most promising research results in this field, presented in the form of original articles and high-quality reviews.