A series of metal-organic frameworks (MOFs) containing manganese centers and oligothiophene dicarboxylate linkers have been synthesized: [Mn(3PhT(2)DC)(DMF)(0.4)s(F12.0)2..s5.1.5 5DMF] (1), [Mn6(3F1T2PC)6. (DMF)3(-120)5"xDMF"YH20] (2), [Mn(T3DC)(H20)2] (3), [Mn(T3DC)(H20)1.3] (4), and [Mn(Ph2T3DC)(DMF)2] (5) (H23PhT2DC = 3,3'-dipheny1-2,2-bithiophene-5,5'-dicarboxylic acid; H23HT2DC:= 3,3'-dihexy1-2,2'bithiophene-5,5'-dicarboxylic acid; H2T3DC = 2,2':5',2"".ter,thiophene-5,5 '-dicarboxylic acid; H2Ph2T3DC = 3',4'-dipheny1-2,2':5',2"-terthiophene-5,5"-dicarboxylic acid, DMF = N,N-dimethylformamide). Compound 1 exists as a 2D sheet, 2-4 are 3D frameworks, and 5 is a ID chain. Compounds 3 and 4 are " isomers, and 3-5 are the first examples of crystallographically characterized terthiophene coordination polymers. In the case of 1, 2, and 5, the extended structure is sensitive to beta substitution of the oligothiophene linkers. Compounds 1-3 and S show antiferromagnetic behavior with typical values of g and J, and 3 exhibits a spin canting transition at 40 K.