Reported here are the syntheses, structures, and characterizations of four novel In−Sb−S compounds containing organic amines, namely, [PAH] 3 [In 3 Sb 2 S 9 ] (PA = npropylamine) (1), [Fe(en) 3 ][In 2 Sb 2 S 7 ] (en = ethylenediamine) (2), [Mg(dien) 2 ][In 2 Sb 2 S 7 ]·0.5H 2 O (dien = diethylenetriamine) (3), and In 2 (N,N-dmen) 2 Sb 2 S 6 (N,N-dmen = N,N-dimethylethylenediamine) (4). Compound 1 features a [In 3 Sb 2 S 9 ] n 3n− layer assembled by the alternating linkage of the {In 2 Sb 2 S 8 } n ribbons and the {In 4 Sb 2 S 12 } n double-ribbons. Both compounds 2 and 3 possess layered anionic parts with the same stoichiometry of [In 2 Sb 2 S 7 ] n 2n− but distinct linkage modes between the subunits of {In 2 S 7 } groups and Sb 3+ ions. Notably, the {In 2 Sb 2 S 9 } heterometallic cluster observed in 3 is initially regarded as the secondary building unit (SBU) for the construction of the [In 2 Sb 2 S 7 ] n 2n− layer. Compound 4 features a novel discrete inorganic−organic hybrid molecule of In 2 (N,N-dmen) 2 Sb 2 S 6 . Through the structural analyses on 1−4, the organic amines applied played three different roles on the formation of the final crystalline products. For 1, the protonated n-propylamines arrange in the space around the anionic network and balance the negative charge. For 2 and 3, the chelating polyamines coordinate to central metal ions to form metal complexes, which then act as space-filling and charge-balancing agents. For 4, two N,N-dimethylethylenediamines chelate to two In 3+ ions of the inorganic segment through coordination bonds, leading to the formation of a rare inorganic−organic hybrid cluster. At last, we gave a systematic discussion about the characteristics and roles of organic amines in all related In−Sb−S compounds. In one word, the work presented here enriches the structural chemistry of the main-group heterometallic chalcogenidometalates, providing more chances for researchers to work out the rules in their composition− or structure−function relationship.