Molecular and electronic structure of mono-, di-, tri- and tetrabenzoporphyrins with iron (II) was carried out by quantum-chemical method of density functional theory B3LYP/6-31G(p,d). It was shown that triplet electronic spin state is a ground state for them. The energy of quantum yield of this state for all compounds excluding cis-configuration of iron-dibenzoporphyrin is enough to singlet oxygen formation. The smallest wavelength in adsorption spectra of examined structures has a place in the interval of 446-550 nm. These facts are preferable for practice use of iron-benzoporphyrin derivatives for photodynamic therapy of cancer diseases.