The magnetic susceptibility of ((CH3)2CHNH3)2CuCl4 is measured in the temperature range 340 to 78 K. The susceptibility changes abruptly near the thermochromic temperature of 56°C. The compound obeys the Curie‐Weiss behaviour at high temperatures, but seems to behave like a two‐dimensional ferromagnet at lower temperatures. A good fit between experimental and theoretical results is obtained using a Heisenberg ferromagnetic simple quadratic lattice model, this yields a J/K = 12.5.