The behavior of poly(l-lactide) (PLLA) complexes containing copper and chromium both in solution and in solid state was investigated by using viscometry, spectroscopy, thermogravimetry, and differential scanning calorimetry. The formation of these complexes leads to fluctuations in typical parameters such as viscosity and the Huggins and Kraemer constants due to conformational changes experienced by certain macromolecules with donor or acceptor groups in the presence of strongly loaded metallic ions. Crystallization temperatures fell considerably as the metallic complexes were formed; in other words, crystallization and its starting temperature were both reduced, although the complexes exhibited greater thermal stability. This affected the degradation characteristics of PLLAmetal complexes. The stretching vibrations of the ester group shifted to a lower frequency, which indicates the involvement of CO groups in coordination with metal ions. (c) 2012 Wiley Periodicals, Inc. Adv Polym Techn 32: E297E305, 2013; View this article online at wileyonlinelibrary.com. DOI 10.1002/adv.21277