A Curtius-like rearrangement of hydroxamates to isocyanates was discovered. This reaction was initiated from an iron(II)-nitrenoid complex, which was generated by the iron(II)-catalyzed cleavage of N-O bonds of functionalized hydroxamates. To demonstrate the efficiency of this new Curtius-like rearrangement in synthetic chemistry, a biomimetic strategy for the one-pot preparation of bisindolylmethanes was developed.