High-throughput microporous tube-in-tube microchannel reactor (MTMCR) was first designed and developed as a novel gas-liquid contactor. Experimentally measured k(L)alpha in MTMCR is at least one or two orders of magnitude higher than those in the conventional gas-liquid contactors. A high throughput of 500 L/h for gas and 43.31 L/h for liquid is over 60 times higher than that of T-type microchannel. An increase of the gas or liquid flow rate, as well as a reduction of the micropore size and annular channel width of MTMCR, could greatly intensify the gas-liquid mass transfer. The interfacial area, a, in MTMCR was measured to be as high as 2.2 x 10(5) m(2)/m(3), which is much higher than those of microchannels (3400-9000 m(2)/m(3)) and traditional contactors (50-2050 m(2)/m(3)). The artificial neural network model was proposed for predicting a, revealing only an average absolute relative error of <5%. (C) 2010 American Institute of Chemical Engineers AIChE J, 57: 239-249, 2011