A novel two-dimensional cobalt(II)-based metal–organic framework (Co-MOF) was synthesized using com
bined solvothermal and sonochemical methods. The structure of the compound, [Co(HL)(bipy)(H2O)]n (H3L=
m-(phosphonomethyl)benzoic acid), was determined by single-crystal X-ray diffraction and confirmed to
form a two-dimensional coordination polymer. The nanostructured form (Co-MOF’) was obtained via
ultrasonic irradiation and comprehensively characterized by FT-IR, PXRD, SEM, EDX, TGA, and BET tech
niques. The Co-MOF’ exhibited excellent catalytic performance in the one-pot synthesis of 3,4-dihydro
pyrimidinones (DHPMs) via the Biginelli reaction under green, solvent-free conditions. The catalyst
offered high product yields (up to 97%) within short reaction times (30 min), remarkable recyclability over
seven cycles without significant loss of activity, and superior performance compared to previously
reported MOF-based catalysts. This study highlights the potential of Co-MOF’ as an efficient, reusable,
and environmentally benign heterogeneous catalyst for multicomponent organic transformations.