The title compound, {[Mn(C(10)H(28)N(6))][Sn(3)Se(7)]}(n), consists of anionic (infinity){[Sn(3)Se(7)](2-)} layers interspersed by [Mn(peha)](2+) complex cations (peha is pentaethylenehexamine). Pseudocubic (Sn(3)Se(4)) cluster units within each layer are held together to form a 6(3) net with a hole size of 8.74 x 13.87 A. Weak N-H...Se interactions between the host inorganic frameworks and metal complexes extend the components into a three-dimensional network. The incorporation of metal complexes into the flexible anion layer dictates the distortion of the holes.