Pyrazolyl-based zinc(II) carboxylate complexes: synthesis, characterization and catalytic behaviour in ring opening polymerization of ε-caprolactone and D,L-lactide

•Mononuclear and polymeric (pyrazolyl)zinc(II) benzoates were synthesized from pyrazolyl ligands and zinc benzoates.•(Pyrazolyl)zinc benzoates with electron-withdrawing groups are mononuclear.•Whereas (pyrazolyl)zinc benzoates without electron-withdrawing groups are polymeric.•Both types of zinc complexes are good initiators for the ring opening polymerization of ɛ-caprolactone and D,L-lactides.•The polycaprolactone and polylactides are low molecular weight polymers.