Under hydrothermal conditions, two 2D coordination polymers based on methylenediisophthalic acid (H 4 L) and 1,2-bis(imidazole-1-ylmethyl)benzene/1,3-bis(imidazole-1-ylmethyl)benzene (o-bix/m-bix) connectors were prepared and characterized by single crystal X-ray diffraction, IR and TG analysis. The structural analysis shows that complexes 1–2 have interesting unsquare 4-connected topological nets. Complex 1 has the Schläfli symbol (3 2 .4.6 2 .7) 2 (3 2 .6 2 .7 2 ) with the distorted β-W net and complex 2 has the seldom reported Schläfli symbol (3.4.5.6 2 .7) 2 (3.4 2 .5 2 .7). Moreover, there exist 1D helical chains [M 2 (bix) 2 ] ∞ (M=Ni II and Co II ) in 2D chiral layer of 1 and 2D nonchiral layer of 2.