"Reactive intermediates" is an important topic in basic organic chemistry courses. Among different reactive intermediates, carbene & nitrene being neutral and highly electron deficient species play a significant role in various organic transformations. In this course we will disclose its generation, stability, structure, reactivity etc. Next, the application of these reactive intermediates in various organic reactions will be disclosed in detail. Furthermore, the course will accommodate related assignments which might help in various competitive exams in future.