•3-Pyrazolyl-pyran-2-one was synthesized using two conditions.•Crystal structure and DFT are discussed in comparative study.•Hirshfeld surface analysis and energy frameworks calculations were described..•Mulliken and QTAIM atomic charges, NBO, MEP, HOMO-LUMO were computed.•In silico ADME parameters have been studied. Synthesis, crystal structure, Hirshfeld surface analysis, DFT and in-silico studies were carried out for the 4‑hydroxy-6-methyl-3-(1-phenyl-1H-pyrazol-3-yl)-2H-pyran-2-one 2. The reaction efficiency was evaluated performing two conditions to prepare the Vilsmeir-Haack reagent: phosphoryl trichloride in DMF and phosphorus pentachloride in DMF. The molecular structure was confirmed by 1H and 13C NMR, IR spectroscopy and X-ray diffraction analysis. The pyrazole and pyran rings are nearly coplanar. The molecules are connected through C—H···O hydrogen bonds, C—H⋯π and π⋯π stacking interactions, forming layers in the crystal lattice. Hirshfeld surface analysis for crystal packing indicates that the most important contributions are H⋯H (41.6 %), C⋯H/H⋯C (22.6 %), O…H/H…O (20.9 %) interactions. The frontier molecular orbital, Mulliken and QTAIM atomic charge, Molecular Electrostatic Potential, Natural Bond Orbitals were produced using the optimized structure by B3LYP/6–311G(d,p) level of theory. The calculated LUMOHOMO gap (4.261 eV) indicated that the eventual charge transfer and showed chemical reactivity. Intrinsic reaction coordinate (IRC) calculation confirm that the transition state connects the reactants to the products. The experimental geometry parameters of the title compound are compared with the geometry of the optimized molecule in the gas phase and found in good agreement. The crystal structure was further explored to define the interaction energy between the molecular pairs. The ADME profile that pyrazolyl-pyran-2-one 2 is an inhibitor of CYP1A2 one of the five key cytochrome isoforms enzymes involved in drug metabolism. Display omitted