A dinuclear Ni(II) complex involving tetrathiafulvalene (TTF) radicals as ligands has been prepared and characterized, [Ni-2(mu-Cl)(2)(L center dot+)(2)](I-3)(4)(I-2)(3)center dot(H2O)(2)center dot(C4H8O)(3) (1), L = 4,5-bis(2-pyridylmethylsulfanyl)4',5'-ethylenedithiotetrathiafulvalene. There are two types of intramolecular magnetic exchange interactions, namely one ferromagnetic Ni(II)-Ni(II) and one antiferromagnetic Ni(II)-TTF center dot+. This study is new in the respect of revealing a magnetic exchange interaction between a TTF center dot+ radical and a paramagnetic transition metal ion. This is due to the fact of a direct binding of the transition metal ion to the skeleton of the TTF center dot+ radical.