The role of substituents on resonance assisted hydrogen bonding (RAHB) vs. intermolecular hydrogen bonding is highlighted in known arylhydrazones of active methylene compounds (AHAMCs) and in their new representatives – ( E / Z )-2-(2-( para -substitutedphenyl)hydrazineylidene)- N , N -diethyl-3-oxobutanamides (–C 2 H 5 , –H, –COOH, –CN). The strength of the H-bond depends on the attached functional groups to both the active methylene fragment and the aromatic moiety of the AHAMC. For instance, attachment of the strong electron donor group –N(C 2 H 5 ) 2 ( σ p = −0.72) to the active methylene fragment of AHAMC allows to isolate this class of compounds without RAHB but with strong intermolecular H-bonds, which are the first examples reported herein.