Crystal structure and Hirshfeld surface analysis of 2,6-bis-[4-(eth-oxy-carbon-yl)-5-methyl-pyrazol-1-yl]pyridine.

The title compound (systematic name: ethyl 1-{6-[4-(eth-oxy-carbon-yl)-5-methyl-pyrazol-1-yl]pyridin-2-yl}-5-methyl-pyrazole-4-carboxyl-ate), C19H21N5O4, consists of a central pyridine ring substituted by two functionalized pyrazole rings and crystallizes in the centrosymmetric space group C2/c. The pyridine-pyrazole and pyrazole-pyrazole dihedral angles are 30.55 (5) and 50.81 (8)°, respectively, indicating significant deviations from coplanarity. An intra-molecular C-H⋯O hydrogen bond stabilizes the mol-ecular conformation. In the crystal, mol-ecules form columns along the c-axis, but large centroid separations and offsets between parallel pyridine rings contribute to the absence of π-π stacking. Inter-molecular C-H⋯N and C-H⋯O hydrogen bonds link mol-ecules into a three-dimensional network. Hirshfeld surface analysis shows that H⋯H contacts dominate the packing (49.9%), with hydrogen-involving inter-actions contributing over 90% of all contacts. The mol-ecular shape is moderately anisotropic, with globularity and asphericity values of 0.677 and 0.395, respectively. These results highlight the key role of hydrogen-based inter-actions in directing the supra-molecular organization and crystal cohesion.