5-APB, formally known as 5-(2-aminopropyl)benzofuran, is a synthetic benzofuran compound belonging to the phenethylamine and amphetamine chemical families. It is structurally related to compounds such as 6-APB and is primarily referenced in analytical chemistry, forensic toxicology, and neuropharmacological research.

Due to its benzofuran core structure, 5-APB has been studied for its interaction with monoamine neurotransmitter systems, including serotonin, dopamine, and norepinephrine transporters. These properties make it relevant in comparative research involving entactogenic and stimulant-class substances. In laboratory settings, 5-APB is typically encountered as an off-white crystalline powder, commonly in salt form to enhance stability and reproducibility during analysis.

5-APB has no approved medical or therapeutic use. Its legal classification varies by region, and it is most commonly discussed in scientific literature, chemical identification databases, and harm-reduction documentation rather than clinical applications.