A new series of gadolinium complexes with mixed ligands, dialkyl dithiocarbamate and 1,10-Phenantroline were successfully synthesized using “in situ” methods. Microelemental analysis data of complexes are in agreement with the general formula Gd[S2CNR’R”]3Phen (R’ = ethyl, methyl; R” = butyl, heptyl, isopropyl, isobutyl, benzyl and cyclohexyl; Phen = 1,10-phenantroline). These complexes have been characterized using elemental analysis, infrared, thermogravimetric analysis, conductivity and magnetic measurements. Infrared spectra of complexes showed the thioureide n(C-N) bands were in the region of 1450 - 1490 cm-1. The single n(C-S) bands appeared in the region of 959 – 1003 cm-1 and n(C-H) bands in the region of 2853-2931 cm-1. The crystal structure of tris(N,N-methylbenzyldithiocarbamate)(1,10-phenantroline) gadolinium(III) adopts a triclinic system (space group Pī) with a distorted dodecahedron geometry with a = 11.04(6) Å , b = 12.65(7) Å, c = 17.13(10) Å, a =73.86o(8) b =74.54o(8) g = 72.34o(8) and Z = 2. Three dithiocarbamates and one phenanthroline ligands were coordinated to the central Gd atom in bidentate manner.