Mn(L-Phe)2稨2O]n (Phe=phenylalanine) with a single stranded coordination poly- mer has been synthesized by self-assembly of manganese salt and phenylalanine and characterized by X-ray single-crystal diffraction method. The complex crystallizes in the orthorhombic, space group P212121 with a = 6.0911(1), b = 10.3642(1), c = 30.4321(7) ? V = 1921.16(6) ?, Z = 4, Dc = 1.387 g/cm3, C18H22N2O5Mn, Mr = 401.32, F(000) = 836 and m(MoKa) = 0.717 mm-1. The final R = 0.0614 and wR = 0.1412 for 2291 observed reflections with I > 2s(I). The magnetic behavior study shows that there exist super-exchange antiferromagnetic interactions between the magnetic centers through the effective exchange pathway of the carboxylate group. Mn (L-Phe) 2 稨 2O] n (Phe = phenylalanine) with a single stranded coordination poly-mer has been synthesized by self-assembly of manganese salt and phenylalanine and characterized by X-ray single-crystal diffraction method. The complex crystallizes in the orthorhombic space group P212121 with a = 6.0911 (1) b = 10.3642 (1) c = 30.4321 (7) V = 1921.16 (6) ?, Z = 4, Dc = 1.387 g / cm3, C18H22N2O5Mn , Mr = 401.32, F (000) = 836 and m (MoKa) = 0.717 mm-1. The final R = 0.0614 and wR = 0.1412 for 2291 observed reflections with I> 2s (I). The magnetic behavior study shows that there exist super-exchange antiferromagnetic interactions between the magnetic centers through the effective exchange pathway of the carboxylate group.