Triazene is one of the most versatile building blocks in organic synthesis. Generally, it is viewed as a safe equivalent of diazonium salt, thus immediately finding numerous applications in preparative chemistry and medicinal chemistry. Besides, it can be used as a removable directing group in C-H functionalization or play a smart role as a precursor for aryl cation/radical generation. In this review, we will highlight recent noteworthy developments in this field.