Persistent carbene adducts and methods of forming the same are generally described, as well as compositions comprising the persistent carbene adduct. In some embodiments, methods are provided comprising heating a persistent carbene to relatively high temperatures to convert the persistent carbene into a persistent carbene-carbodiimide adduct. In certain embodiments, the percent of the persistent carbene that is converted to the persistent carbene-carbodiimide adduct is relatively high (e.g., at least about 50%). In some embodiments, the persistent carbene-carbodiimide adducts formed via the methods described herein may be relatively stable. Compositions comprising the persistent carbene-carbodiimide adducts of the present invention may be useful for applications involving catalysis, organometallic chemistry, sensing, and surface functionalization, amongst others.