Chiral cyanido-bridged Mn-Nb magnets including halogen-bondsElectronic supplementary information (ESI) available: Details of synthetic methods, physical techniques, the selected crystallographic data, the results of continuous shape measurement (CShM) analysis, the UV-vis and IR spectrum, the additional temperature-dependent magnetization plots, and the result of the SH light measurement. CCDC 1854369-1854374. For ESI and crystallographic data in CIF or other electronic format see DOI: 10.1039/c

Three-dimensional cyanido-bridged bimetallic assemblies [Mn II (4-Xpy) 4 ] 2 [Nb IV (CN) 8 ]· n H 2 O (4-Xpy: 4-halopyridine; X = I and n = 0, ( 1 ); X = Cl and n = 0.5, ( 2 )) are synthesized. 1 and 2 have chiral and achiral structures, respectively. The chiral structure of 1 is composed of achiral building blocks, which lead to an enantiopure compound through a spontaneous resolution process. In the crystal structure of 1 , the halogen bonds between 4-Ipy and cyanide distort the structure, lowering the crystal symmetry. Both 1 and 2 show ferrimagnetism with Curie temperatures ( T C ) of 22 K and 28 K, respectively. Due to the chiral and polar structure in the I 4 1 space group, 1 exhibits SHG phenomena, while such nonlinear optical phenomena are quenched in 2 due to its centrosymmetry. Chiral and achiral three-dimensional cyanido-bridged metal assemblies with 4-halopyridine, [Mn II (4-Xpy) 4 ] 2 [Nb IV (CN) 8 ] (X = I, 1 ; X = Cl, 2 ), are prepared. 1 and 2 show ferrimagnetism with T C of 22 and 28 K, respectively. Chiral compound 1 exhibits second-harmonic generation.