Grey crystals of AgBi ₂S ₃Cl and AgBi ₂Se ₃Cl were synthesized from AgCl and Bi ₂S ₃ or Bi ₂Se ₃ by cooling stoichiometric melts from 790 K to room temperature. X-ray diffraction on powders and single-crystals revealed that the compounds crystallize isostructural with space group type P 2 ₁/m. In the crystal structure of AgBi ₂S ₃Cl the bismuth(III) cations have a capped trigonal prismatic coordination of sulfide and chloride ions. The prisms constitute a three-dimensional framework by sharing common edges and faces. Silver(I) cations, which have a distorted octahedral coordination of sulfide ions, fill linear channels. Parallels to the crystal structures of Cu ₃Bi ₂S ₄Cl and Pr ₂Br ₅ can be seen.