A new open-framework indium sulfide ([In12S24H2]10-) constructed from pentasupertetrahedral sulfide clusters ([In8S17H],9- P1) and supertetrahedral sulfide clusters ([In4S10H],7-) T2) has been prepared through hydrothermal synthesis. Unlike previously reported P1 clusters that require divalent metal cations, the P1 cluster reported here consists of only trivalent ions (In3+) and is the only known example of tetrahedral clusters with a core sulfur site bonded to four trivalent ions. Each P1 cluster is joined to three T2 clusters (vice versa) to form an infinite two-dimensional sheet stacked along the crystallographic c-axis. In contrast with known three-dimensional open-framework indium sulfides in which locations of extraframework amines are rarely known due to disorder, structure-directing amine molecules are much less disordered as a result of host-guest N-H...S hydrogen bonding. The UV-vis diffuse reflectance spectrum shows that this material is a wide band gap semiconductor.