Three heterometallic Cr-Mn compounds, {Mn(mu-ox)(0.5)(H2O) [Cr(phen)(CN)(4)]}(n) (.) nH(2)O(.)2nCH(3)OH, (1), {Mn(mu-ox)(0.5)(-H2O)[Cr(bpy)(CN)(4)]}(n) (.) 2nH(2)O(.)nCH(3)OH, (2), and {Mn(mu-ox)(0.5)(bpy)[Cr(bpy)(CN)(4)]}(n), (3) (ox = oxalate), containing cyanide and oxalate bridges based on building blocks [Cr(L)(CN)(4)](-) (L = phen and 2,2'- bipyridine) have been prepared. A new approach was first employed to synthesize ox-bridged compounds via facile oxidation-hydrolysis reactions of diaminomaleonitrile. X-ray crystallography revealed that the structures of 1 and 2 are similar, where cyano-bridged corrugated ladderlike chains are further connected through bis-bidentate oxalato bridges to unique two-dimensional layered structures. Of note is that the introduction of 2,2'-bipyridine led to an interesting cluster-based chainlike compound (3) with cyano-bridged squares [Mn2Cr2] extended by ox bridges. Magnetic studies show antiferromagnetic (AF) interaction between cyano-bridged Cr-III-Mn-II and ox-bridged Mn-II-Mn-II ions, with the result that 1 and 2 exhibit AF ordering with spin-flop behaviors below 18 and 19 K, respectively.