Microdroplet chemistry, which takes advantage of the air-liquid interfacial effect of tiny droplets, has become a popular tool in various fields such as analysis, reaction monitoring, organic synthesis, and biological and environmental studies. While many studies have reported accelerated reactions in microdroplets, the extraordinary reactivities including three-component Mannich-type reactions, hydrolysis of esters, tandem amide formation, the synthesis of gold-histidine complexes, and bromination of 1,2,3triazoles have realized at the gas-water interface in aqueous microdroplets (pure water or water/organic binary solvents with more than 50% water). However, this extraordinary reactivity remains unexplored at the gas-organic interface, which is highly desirable considering a major use of organic solvents. It is undoubtedly beneficial to uncovering the inherent mechanisms and further broadening the applicability of the unique reactivity of microdroplet chemistry. In addition, the extraordinary reactivity implies a novel possible strategy for divergent reactions other than temperature (Scheme 1A), catalyst type (Scheme 1B) and ligand for metal catalysts (Scheme 1C), and solvent strategies (Scheme 1D), which has not been fully understood. In this study, we first discovered the unique reactivity at the gas-organic interface by using organic microdroplets Mannich-type reactions. 1,4-Benzodiazepines with a main skeleton of benzofused N-heterocycles are important drugs to relieve insomnia and anxiety, and also to treat muscle spasm and prevent seizures. Benzofused N-heterocycles can be constructed from i) ring expansion of 1,3-diazaheterocycles via aryne insertion into a C(sp 3 )-N σ-bond, ii) cyclization reaction of N-(chloroacetyl)-2aminobenzophenone derivatives with hexamethylenetetramine in the presence of NH4OAc, iii) deprotection and cyclization after Ugi-4CR route, and iv) one-pot reaction of Ncarboxyanhydrides and o-ketoanilines promoting benzodiazepine formation with a two-stage process. In this work, we presented a simple, green and high-efficient strategy to construct vicinal diamines and benzofused N-heterocycle from the same imidazoline precursor using two different reactors (vicinal diamines by microdroplets and benzofused N-heterocycle by bulk counterpart) (Scheme 1E). C-N bond is a key and universal structural skeleton in thousands of natural products, which has a decisive impact on the biological properties of drug molecules. The "inside-outside" C-N bond could be broken selectively under different catalytic conditions, and new multi-purpose and highperformance arylation/acylation/transamination reagents were developed (Scheme 2A). In 2020, the imidazolidinone ring of 1,3-dihydro-1H-benzimidazol-2-one was opened by Ph3P-I2, and the C-N bond in the five membered ring was broken to form aryliminophosphoranes (Scheme 2B). However, the C elements of these broken C-N bonds were all connected with carbonyl functional groups, while the relevant research on N-C-N bond cleavage is rare. Imidazolines, basically a partially saturated analog of imidazole, are high-value in medical, pharmaceutical, laundry and other uses. Ring opening of imidazoline has been used to study the ring-chain tautomerism of 1,3-disubstituted diazolidines under acidic conditions (Scheme 2C). However, double cleavage of carbon-nitrogen bonds of imidazoline compounds has never been reported. Herein we reported a novel pathway to form 1,2-diamines by the on-pot double cleavage of two C-N bonds in imidazoline derivatives (Scheme 2D). In comparison with previous method for constructing diamines, the proposed pathway in this work is simple, high-efficient, and mild. Moreover, the double C-N bond breakdown for the construction of vicinal diamines was the first example of extraordinary reactivities of organic microdroplet chemistry (Scheme 3). Five membered ring of an imidazoline derivative 1a was opened chemoselectively only in organic microdroplets, in which two C-N bonds were broken in one pot to form vicinal diamines in milliseconds. Instead, two different products, majorly benzofused 7-membered N-heterocycle 3a from rearrangement of a ring-open intermediate and minorly imine 4a were offered in bulk phase under harsh conditions after overnight reaction. Scheme 3. Ring opening of imidazoline derivative 1a to generate vicinal diamine in microdroplet and benzofused 7-membered N-heterocycle and imine in bulk phase.