were detected from the collection solutions of both microdroplet and bulk reactions, and the abundance ratio of the two peaks by the microdroplet reaction was significantly higher than the bulk reaction. These MS results not only confirmed the elimination of methylene in the form of formaldehyde but indicated different reaction pathways driven by organic microdroplet chemistry in higher efficiency than its bulk counterpart. We also performed a control experiment to check how the imine product 4a was formed. Purified vicinal diamine 2a and rearrangement benzofused N-heterocycle 3a were individually stirred in acidic acetonitrile (18.4 equiv.