Syntheses, crystal structures, Hirshfeld surface analyses and energy frameworks of two 4-amino­anti­pyrine Schiff base compounds: (E)-4-{[4-(di­ethyl­amino)­benzyl­idene]amino}-1,5-dimethyl-2-phenyl-1H-pyrazol-3(2H)-one and (E)-4-[(4-fluoro­benzyl­idene)amino]-1,5-dimethyl-2-phenyl-1H-pyrazol-3(2H)-one

The title Schiff base compounds, C(22)H(26)N(4)O (I) and C(18)H(16)FN(3)O (II), were each synthesized by a single-step condensation reaction. The substituted benzyl­idene ring is inclined to the pyrazole ring mean planes by 22.92 (7)° in I and 12.70 (9)° in II. The phenyl ring of the 4-amino­anti­pyrine unit is inclined to the pyrazole ring mean plane by 54.87 (7)° in I and by 60.44 (8)° in II. In the crystal of I, the mol­ecules are linked by C—H⋯O hydrogen bonds and C—H⋯π inter­actions to form layers lying parallel to (001). In the crystal of II, the mol­ecules are linked by C—H⋯O and C—H⋯F hydrogen bonds and C—H⋯π inter­actions, thereby forming layers lying parallel to (010). Hirshfeld surface analysis was employed to further qu­antify the inter­atomic inter­actions in the crystals of both compounds.