Single crystals of organically templated chiral bromobismuthates(III), [(( R / S )-C 8 H 12 N) 4 ][Bi 2 Br 10 ], have been grown for the first time via a slow evaporation method. Each of the chiral molecular compound consists of ( R ) or ( S )-1 - phenylethylammonium ([C 8 H 12 N] + ) cations and [Bi 2 Br 10 ] 4– anions. Both the title compounds reveal thermal and moisture stabilities up to ca. 220 °C and over 1 month, respectively. The newly prepared Bi 3+ -based organic–inorganic hybrid materials show optical band gap of ca. 2.88 eV. The noncentrosymmetric [(( R )-C 8 H 12 N) 4 ][Bi 2 Br 10 ] and [(( S )-C 8 H 12 N) 4 ][Bi 2 Br 10 ] exhibit second harmonic generation efficiency of ca. 20 times that of α-SiO 2 and are type I nonphase matchable. Uniformly deposited thin films of [(( R )-C 8 H 12 N) 4 ][Bi 2 Br 10 ] and [(( S )-C 8 H 12 N) 4 ][Bi 2 Br 10 ] have been also successfully obtained by a simple spin-coating method. The circular dichroism spectra for both reported thin films are symmetrical, attributable to the corresponding Cotton effect. The selectively deposited chiral thin films are expected to be used as a useful platform for various surface reactions and interface engineering.

Two positional isomers, 4-amino-3-methylpyridine and 3-amino-5-methylpyridine, produce 4-amino-3-methylpyridinium and 5-methylpyridin-3-aminium, respectively, under acidic conditions. The two protonated isomers create different hydrogen bonding networks, resulting in different coordination environments of the [MnX4]2– unit embedded in molecular compounds such as 4-amino-3-methylpyridinium manganese bromide, [(C6H9N2)2MnBr4] and 5-methylpyridin-3-aminium manganese bromide, [(C6H9N2)4MnBr4(H2O)·(MnBr4)]. Both compounds can be prepared using the slow evaporation method or mechanochemical synthetic procedures. Single-crystal structure analysis of [(C6H9N2)2MnBr4] and [(C6H9N2)4MnBr4(H2O)·(MnBr4)] revealed different manganese halide units, including tetrahedral and tetrahedral with distorted trigonal bipyramidal structures, which emit photoluminescence in the green (527 nm) and red (607 nm) regions, respectively. Electronic structure calculations were conducted to support the validity and interpretation of the UV–vis and photoluminescence (PL) spectral data. Thin films deposited using the [(C6H9N2)2MnBr4] precursor also exhibit PL properties. The diverse pseudo-three-dimensional networks can be constructed by using positional isomers with different hydrogen bonding pathways and π–π stacking of organic units, in which the design strategy successfully enables the tuning of various optical properties.