The success of chemoselective synthesis of vicinal diamine 2a by the accelerated microdroplet ring opening reaction prompted us to explore the scope of imidazoline derivatives including six imidazoline reactants 1b-1g bearing electron-attracting and donating groups (methyl, trifluoromethyl, fluoro, and phenyl) on the meta-/para positions of the two phenyl cycles with similar motifs to the model reactant 1a (see the synthesis of these starting materials in S2). The ring opening reactions of these imidazoline derivatives were carried out under the above optimized conditions unless stated else, and the yields measured by HPLC are listed in Scheme 4. Three conclusions can be drawn from the result in Scheme 4. First, all of the imidazoline derivatives can be chemoselectively converted into their corresponding vicinal diamines 2 with satisfactory yields (> 90%) by organic microdroplet chemistry. In contrast, the rearrangement benzofused N-heterocycle products 3b-3d and 3f-3h can be chemoselectively produced with moderate yields (31%~69%) in the bulk reactions (proton and carbon nuclear magnetic resonance spectra in Figure -S52, and high-resolution mass spectra in Figure ). It further confirmed the specific role of organic microdroplet chemistry in driving different reactivity from its bulk counterpart. Second, the reaction efficiency by organic microdroplet chemistry was improved by at least four orders of magnitude relative to the bulk as evidenced from a rough comparison between reaction times (less than 1 ms in microdroplets versus > 12 hours in bulk). Considering the yield superiority of organic microdroplet chemistry (> 90%) over the bulk (< 60%), the reaction efficiency may be further enhanced by organic microdroplet chemistry. Last, neither electron-donating nor electronattracting substituted groups born by the imidazoline derivatives 1 had observable interfering effect on the ring opening reaction by the microdroplet method. However, the rearrangement reaction in bulk was moderately affected when the N-phenyl of imidazoline derivatives were para-substituted. To further demonstrate the feasibility of the chemoselective synthesis by organic microdroplet chemistry and the bulk, a general imidazoline derivative reactant 1h was also tested. The microdroplet reaction can still proceed smoothly to quantitatively yielding the vicinal diamine product 2h by using the reactant 1h (Scheme 4, Entry 8), and the bulk reaction also chemoselectively generated the rearrangement product 3h with a moderate yield (47%). These results proved the advantages of organic microdroplet chemistry including high reaction selectivity, high reaction efficiency and wide substrate scope, showing considerable application potential in organic synthesis.