Chemical transformations used in fine chemical manufacturing often involve two-phase interaction for which mass transfer limitations can lead to prolonged reaction time and reduced productivity. We present a high-performance miniature continuous stirred-tank reactor (CSTR), with non-contact magnetic coupling providing intensive agitation inside the sealed miniaturized chamber. High-speed imaging of the biphasic hydrodynamics gives an estimated mass transfer coefficient (k(L)a) on the order of 10 s(-1), comparable to commercial passive mixing flow reactors. Case studies with two important biphasic C-C bond-forming reactions: (i) asymmetric alkylation catalyzed by cinchonidine-derived phase-transfer catalyst, and (ii) biphasic Suzuki-Miyaura C-C coupling reactions, demonstrate the versatility of the CSTR unit. Moreover, a detailed kinetic model proposed for phase-transfer reaction systems controlled by the Makosza interfacial mechanism further cross-validates the mass transfer coefficient estimates.