The ringexpansion of small-ring compounds provides a powerful method for the construction of various cyclic compounds. Herein, nitrene equivalent mediated metal-free ringexpansions of alkylidenecyclopropanes (ACPs) and an alkylidenecyclobutane (ACB) were described. In this synthesis, a series of aryl-substituted cyclobutylidene and cyclopentylidene hydrazine derivatives were obtained under mild conditions