A family of polymeric 1-dimensional chains of iron (II) species showing the spin-crossover phenomenon has been synthesized using 4-n-alkyl-1, 2, 4-triazoles as bridging ligands. The influence of the length of the alkyl tails on the triazole ligands on characteristic features of the spin transition was studied, showing degrading of steepness with increasing length. A set of four counter ions has been used to access a wider range of transition temperatures. ...