A comparison of the supramolecular structures of 1-(6-amino-1,3-benzodioxol-5-yl)-3-(3,4,5-trimethoxyphenyl)prop-2-en-1-one and 1-(6-amino-1,3-benzodioxol-5-yl)-3-[4-(N,N-dimethylamino)phenyl]prop-2-en-1-one.

1-(6-amino-1,3-benzodioxol-5-yl)-3-(3,4,5-trimethoxyphenyl)prop-2-en-1-one, C19H19NO6, (I), contains an intramolecular N-H...O hydrogen bond and a weak C-H...O hydrogen bond, which forms a C10 chain motif running parallel to the c axis. The 6-amino-1,3-benzodioxol-5-yl moieties are involved in pi-pi stacking. 1-(6-amino-1,3-benzodioxol-5-yl)-3-[4-(N,N-dimethylamino)phenyl]prop-2-en-1-one, C18H18N2O3, (II), crystallizes with two molecules in the asymmetric unit. The main feature of the supramolecular structure of (II) is the formation of a centrosymmetric hydrogen-bonded tetramer with an R8(4)(16) motif.