A simple hydrogen-bonded chain in (3Z)-3-{1-[(5-phenyl-1H-pyrazol-3-yl) amino]ethyl-idene}-4,5-dihydro-furan-2(3H)-one, and a hydrogen-bonded ribbon of centrosymmetric rings in the self-assembled adduct (3Z)-3-{1-[(5-methyl-1H- pyrazol-3-yl)amino]ethyl-idene}-4,5-dihydro-furan-2(3H)-one-6-(2-hydroxy-ethyl) -2,5-dimethyl-pyrazolo[1,5-a]pyrimidin-7(4H)-one (1/1)