Treatment of [Mn(CH3COO)(2)center dot 4H(2)O] with two equivalents of K[N(Ph-2 PO)(2)] in the presence of one equivalent of 2,2'-bipyridine (bpy) or 5,5'-dimethyl-2,2'-bipyridine(dmbpy) in ethanol resulted in the formation of the mononuclear manganese(II) complexes [Mn{eta(1)-O-N(Ph2PO)(2)}{N(Ph2PO)(2)}(EtOH)(bpy)] (1) and [Mn{N(Ph2PO)(2)}(2) (dmbpy)] (2), respectively. Interaction of [Mn(CH3COO)(2)center dot 4H(2)O], K[N(Ph2PO)(2)] and salicylaldehyde or 5-chlorosalicylaldehyde or 3,5-dibromosalicylaldehyde in the presence of triethylamine in methanol gave the binuclear manganese0I) complexes [Mn-2{N(Ph2PO)(2)}(2) (mu,eta(2)-O,O'-Sal)(2)(MeOH)(2)](3) and [Mn-2{N(Ph2PO2)(2)}(2)(mu, eta(2)-O,O'-3,5-Br-2- Sal')(2)(MeOH)(2)] (4), and a tetra-nuclear manganese(II)/(III) complex [Mn-2{N(Ph2PO2)(2)}(2)(mu, eta(2)-O,O'-3,5-Br-2- Sal')(2)(MeOH)(4)(mu-OMe)(2)(mu(3)-OMe)(2)] (5), respectively. All complexes were characterized by infrared and ultraviolet spectroscopy, their molecular structures were unambiguously established by single crystal X-ray diffraction. The electrochemical properties of complexes 1-5 were also investigated in the paper.