Two salts containing diphosphorus-Centered radical anion 1(center dot-) and diradical dianion 1(2-center dot center dot) were obtained by one- and two-electron reductions of an indenofluorene-bridging diphosphaalkene (1) with 'K and KC8, respectively. The salts have been characterized by electron paramagnetic resonance (EPR) spectroscopy, UV vis absorption spectroscopy, and Single-crystal X-ray diffraction analysis. EPR spectroscopy and theoretical calculations reveal that the spin density of the radicals mainly resides on the phosphorcis atoms, and 1(2-center dot center dot) has an open-shell singlet ground state 1(-center dot) and 1(2-center dot center dot) represent the first isolable and structurally characterized,diphosphorus-centered radical anion and dianion.