Polyoxomolybdate inorganic organic hybrid crystals were synthesized by using long-tailed primary amine and ionic-liquid surfactants. Dodecylamine and 1-dodecyl-3-methylimidazolium bromide were employed for the syntheses. Both hybrid crystals contained a beta-type octamolybdate (Mo-8) anion and showed alternate stacking of Mo-8 monolayers and interdigitated surfactant bilayers. The arrangement of Mo-8 layers in the inorganic monolayers was different between the hybrid crystals because of the difference in the structures of the surfactant hydrophilic head.