It is well known that simple conventional cooperative octahedral tilts cannot produce non-centrosymmetric structures. This is only true, however, for Brillouin zone-corner tilts. We show here that tilt patterns containing complex tilts can generate noncentrosymmetric structures, by carrying out symmetry analysis of the structures derived from the simplest example of a complex tilt, the ]. We generated a model of a hypothetical Fe[Bi(SCN) 6 ] polymorph possessing these distortions using ISODISTORT and then examined the distribution of NCS -anions. The pseudocubic cages contain 0, 2 or 4 NCS - in the ratio 1:2:6, suggesting that a structure in which 8 of the cages were occupied by A-site cations would stabilise this distortion [Fig. ]. We therefore filled the cages containing 0 or 2 NCS -anions with Cs + cations, producing a model with composition Cs 3 {Fe[Bi(SCN) 6 ]} 4 [Fig. . Very encouragingly our model, which was constructed only taking into account symmetry analysis and counting cage occupancies, was found to be stable with DFT geometry optimisation. We found that moving a Cs + cation into any of the other cages incurred a significant energetic penalty, suggesting that this cation ordering is energetically preferred. This structure is piezoelectric, with the piezoelectricity arising from the complex tilts along the c-axis. The investigation of other stoichiometries and A-site cations will likely be a fruitful route to generating new polar and ferroelectric perovskites.