Ipidacrine (2,3,5,6,7,8-hexa-hydro-1H-cyclo-penta-[b]quinolin-9-amine) was reacted with 4-methoxy-phenyl isocyanate to give the title compound, C(28)H(30)N(4)O(4). An intra-molecular N-H⋯O hydrogen bond results in an essentially planar [r.m.s. deviation from the mean plane is 0.126 (1) Å] conformation for the biuret unit. The central ring of the quinoline unit is twisted by 78.2 (1)° with respect to the biuret mean plane, whereas the two 4-methoxy-benzene rings are twisted out of this plane by 24.3 (1)° and 48.5 (1)°, resulting in an overall propeller-like structure. An inter-molecular N-H⋯N hydrogen bond between the biuret NH atom and the quinoline ring nitro-gen defines the crystal packing.