3,5-Dimethylpyrazole (L), reacts with [Cu(OAc) 2 ] or [Zn(OAc) 2 ]; and either C 6 H 5 COOH, 4-OH–C 6 H 5 COOH, 3,5-NO 2 –C 6 H 5 COOH or 2-Cl–C 6 H 5 COOH to afford the corresponding metal complexes: [Cu(C 6 H 5 COO) 2 (L) 2 ] (1), [Cu(2-Cl–C 6 H 4 COO) 2 (L) 2 ] (2), [Cu(3,5-NO 2 –C 6 H 3 COO) 2 (L) 2 ] (3), [Cu(4-OH–C 6 H 4 COO) 2 (L) 2 ] (4), [Zn(C 6 H 5 COO) 2 (L) 2 ] (5), [Zn(2-Cl–C 6 H 4 COO) 2 (L) 2 ] (6), [Zn(3,5-NO 2 –C 6 H 3 COO) 2 (L) 2 ] (7), [Zn(4-OH–C 6 H 4 COO) 2 (L) 2 ] (8). The diamagnetic zinc complexes were characterized by IR, NMR spectroscopy and elemental analysis; while the paramagnetic copper complexes were only characterized by IR spectroscopy, elemental analysis and 1 and 2 were further characterized by single crystal X-ray diffraction studies. All eight complexes are very good initiators for the ring opening polymerization (ROP) of ε-caprolactone and d,l-lactide at elevated temperatures, under solvent-free conditions and in toluene respectively; producing polycaprolactone (PCL) and poly(d,l-lactide) (PLA) of moderate molecular weights (ca 4757Da for PCL and 2484Da for PLA) and narrow polydispersity indices (1.36 for PCL and 1.42 for PLA). The 13 C{ 1 H} NMR spectra indicate the stereochemistry of PLA is heterotactic.