Because of interest in the 11,12 B(n,γ) reaction in seeding r-process nucleosynthesis through light neutron-rich nuclei, we have measured the 12 B(d,p) reaction for the first time using the ATLAS in-flight facility at Argonne National Laboratory. We also measured the 11 B(d,p) reaction in the same way for calibration. The spectroscopic factors of excited states and the branching ratio of the neutron-unbound state in 12 B are obtained from the current experiment and the reaction rate for 11 B(n,γ) is discussed in comparison with the theoretical prediction.