This paper describes the results of thermodynamic study of dissolution of proto- and mesoporphyrins in liquid N,N-dimethylformamide (DMF) at different temperatures. Enthalpies of solution and solubility of protoporphyrin dimethylester (PDE) and mesoporphyrin dimethylester (MDE) in DMF have been obtained from T = (298 to 318) K. Free energies, enthalpies, entropies and heat capacities of solution have been computed from the combination of enthalpic and solubility data via the Gibbs-Helmholtz equation. We have shown that for all blood porphyrins this approach reproduces both free energies of solution and solubility values for the physiological temperature range. (C) 2015 Elsevier Ltd. All rights reserved.