In order to study calcium ion complex of soya-cerebroside II (1), an ionophoretic glucosylceramide isolated from soybean, C8-cerebroside (3) and 3,3″,6″-trideoxy-C8-cerebroside (4) are designed and synthesized. On the basis of extensive ¹H-NMR studies in the presence of Ca²⁺ and a continuous variation method via ¹H-NMR, soya-cerebroside II is suggested to form a calcium complex with 1/Ca²⁺ ratio of 1 : 1. Soya-cerebroside II serves as a tridentate chelating ligand for Ca²⁺; the amide carbonyl, C2′-hydroxy, and C2″-hydroxy oxygens are responsible for the Ca²⁺ binding. Soya-cerebroside II is structurally analogous to a neural glucosylceramide. Thus, the accumulated neural glucosylceramide inside of endoplasmic reticulum (ER) membrane may serve as an endogenous Ca²⁺-binding and -transport molecule (ionophore) that result in mobilization of Ca²⁺ from intracellular calcium stores.