A 2D layered spin crossover complex, [(FeH3LMe)-H-11]Cl(.)l(3), has been synthesized from the reaction of (FeCl3)-Cl-lll, a tripod ligand (H3LMe= tris[2-(((2-methylimidazoyl-4-yl)methylidene)amino)ethyl]amine), and Nal in methanol. The compound showed an abrupt spin transition between the HS (S = 2) and LS (S = 0) states at T-1/2 = 110 K without hysteresis. The crystal structures of the HS and LS states were determined at 180 and 90 K. A 2D layered structure is composed of (NHCl-)-Cl-... hydrogen bonds between the Cl- ion and three neighboring imidazole groups of [(FeH3LMe)-H-ll](2+). The green light irradiation at 5 K induced the LIESST effect, and the thermal relaxation process from the HS to LS state showed a sigmoid curve at T > 55 K.