Local density and generalized gradient approximation time-dependent density functional methods have been used for calculation of the singlet and triplet excited states of nickel-porphine, Ni-tetraphenyloporphine, and Ni-octaethyloporphyrine. Special attention is paid to metal-ligand transitions and d-d transitions. It is shown that the lowest exited singlet states of the three compounds can be described as a transfer of an electron from the porphine ring to the d(x 2-y 2) orbital of the nickel atom. On the other hand, the lowest excited triplet state arises from promotion of an electron between two nickel d orbitals, an occupied d(z)2 and an empty d(x 2-y 2). It is proposed that a rapid quenching of the excited singlet states is due to an ultrafast intersystem crossing between E-1(g) and E-3(g) or B-3(1g) states. (C) 2004 American Institute of Physics.