雜環化合物是指其分子由含有除碳以外至少一個原子的環表征的任何有機化合物。這些化合物在結構上與環狀有機碳氫化合物相似，但其性質可能與碳氫化合物的性質大不相同，并在很大程度上取決于分子中存在的雜原子的特性、位置和數量。正是這種豐富多樣的物理和生物特性導致了對雜環化合物的深入研究。由此可知，雜環化學是對雜環化合物各個方面的研究。雜環化學起源于有機合成、天然產物化學和藥物化學。實際上，大多數雜環化學家也會認為自己是有機化學家，許多人也會認為自己是天然產物化學家和藥物化學家。學科之間的這種關系之所以產生，是因為雜環分子是生物系統的基本組成部分。雜環化學不僅對生物學有重要意義，而且在染料、光敏劑、配位化合物、高分子材料等許多領域都有著廣泛的研究。

A heterocyclic compound is defined as any organic compound where their molecules are characterized by rings containing at least one atom other than carbon. These compounds are structurally similar to cyclic organic hydrocarbons, but their properties can vary widely from those of their hydrocarbon counterparts and are largely governed by the identity, location and number of heteroatoms present in the molecule. It is this rich diversity of physical and biological properties that has led to intense study of heterocyclic compounds. It follows then that Heterocyclic Chemistry is the study of all aspects of heterocyclic compounds.Heterocyclic chemistry has its origin in organic synthesis, natural products chemistry and medicinal chemistry. Indeed most any heterocyclic chemist will also consider themselves organic chemists and many will consider themselves to be natural products chemists and medicinal chemists as well. This relationship between disciplines arises because heterocyclic molecules are fundamental building blocks of biological systems. In addition to its importance to biology, heterocyclic chemistry has seen intense study in diverse areas such as dyes, photosensitizers, coordination compounds, polymeric materials and many other fields.