In order to assess experimentally the extent to which the nucleation-growth mechanism influences the phenomenon of spin-state crossover in the solid state, variable temperature micro-Raman mapping experiments have been conducted for the first time on the spin-crossover complex Fe(pz)[Ni(CN)(4)]; 2H(2)O. The results point to the absence of domains with dimensions greater than similar to1 micron. (C) 2002 Elsevier Science. B.V. All rights reserved.