A simple hydrogen-bonded chain in (3Z)-3-{1-[(5-phenyl-1H-pyrazol-3-yl)amino]ethylidene}-4,5-dihydrofuran-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]ethylidene}-4,5-dihydrofuran-2(3H)-one-6-(2-hydroxyethyl)