Jahn-Teller active fluoroperovskites <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:mi>A</mml:mi><mml:msub><mml:mi>CrF</mml:mi><mml:mn>3</mml:mn></mml:msub></mml:mrow></mml:math> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mo>(</mml:mo><mml:mrow><mml:mi>A</mml:mi><mml:mo>=</mml:mo><mml:msup><mml:mrow><mml:mi>Na</mml:mi></mml:mrow><mml:mo>+</mml:mo></mml:msup></mml:mrow><mml:mo>,</mml:mo><mml:mspace width="4pt" /><mml:msup><mml:mrow><mml:mi mathvariant…

Chromium (II) fluoroperovskites $A\mathrm{CrF_3}(A\mathrm{=Na^+,K^+})$ are strongly correlated Jahn-Teller active materials at low temperatures. In this paper, we examine the role that $A$-site ion plays in family of using both experimental methods (XRD, optical absorption spectroscopy and magnetic fields) DFT simulations. Temperature-dependent experiments show spin-allowed transitions $E_2$ $E_3$ only merge completely for $A$= Na 2 K. Field-dependent measurements K oscillating strength $\mathrm{NaCrF_3}$ increases with increasing applied field. Direct magneto-structural correlations which suppress spin-flip observed ${\rm KCrF_3}$ below its Ne\'el temperature. NaCrF_3}$ vanish abruptly 9 revealing magneto-optical not linked to crystal structure changes. This suggests as long range ordering is reduced local JT effects individual CrF_6^{4-}}$ octahedra take control behavior. Our results clear deviation from pattern found isoelectronic $A_x{\rm MnF}_{3+x}$ system. The size cation shown be central dictating physical properties phase $A{\rm CrF}_3$, opening up possibility varying composition create novel states matter tuneable properties.