<p>Functional group interconversion, a pivotal synthetic technique for precise editing of molecular building blocks, is particularly rare when facilitated by energy transfer catalysis. Herein, we showcase two instances of photochemical rearrangement of isonitriles, facilitated by energy transfer catalysis under visible light. The di-π-ethane rearrangement and di-π-propane rearrangement proceed through a six-membered transition state, offering a fresh synthetic paradigm for constructing three- and five-membered molecular architectures. Notably, these open-shell rearrangements demonstrate a vast substrate scope, compatibility with diverse functional groups, and applicability to complex drug and natural product derivatives, thereby presenting a complementary strategy for advancing energy transfer-enabled functional group interconversion. Furthermore, the photochemical rearrangements of isonitriles have been supported by computational studies.</p>