The synthesis, structures and semiconducting properties of three isostructural, piperazinium-cation based iodobismuthates, [NH2(CH2)4NH2][BiI4]2·4H2O, [CH3NH(CH2)4NH2][BiI4]2·3H2O and [CH3NH(CH2)4HNCH3][BiI4]2·2H2O, are reported. The materials have pseudo-three dimensional structures consisting of infinite chains formed from edge/face sharing [BiI6] octahedra with short interchain II interactions of <3.8 Å. The materials have band gaps of ∼1.9-2.0 eV and show variable optoelectronic properties based on the degree of methylation of the templating piperazinium ring-based organic species and the accordingly associated level of solvation in the structure.