Single-crystal neutron diffraction at 2.5 K and a subset of neutron data collected at 170 K, combined with information from X-ray diffraction at the same temperature, suggest static disorder for the proton in the short intra­molecular hydrogen bond of 3-[2-(pyridin-4-yl)eth­yl]pentane-2,4-dione.

3-(Pyridin-4-yl)acetyl­acetone (HacacPy) may be used as an N-donor ligand in coordination chemistry and in thermal degradation. After deprotonation of the acetyl­acetone moiety in HacacPy, its metal complexes, Fe(acacPy)₃ and Al(acacPy)₃, can act as poly(pyridine) bridges between hard and soft metal cations.