The melting reaction of Bi with Rh or Ir and BiCl₃ or BiBr₃ yields black, metallic lustrous, air insensitive crystals of the subhalides Bi_12-xMX_13-x (M = Rh, Ir; X = Cl, Br; x < 1). The compounds have the same structural principle as the previously reported subbromide Bi₃₄Ir₃Br₃₇. The structures can be subdivided in four types of complex ionic groups: cuboctahedral [MBi₆X₁₂]^- clusters, [MBi₆X₁₃]^2- clusters with an additional halide ion, Bi₅⁺ square pyramids and distorted Bi₆²⁺ octahedra. The range of homogeneity is due to variable contributions of the different clusters. Bi_12-xIrCl_13-x is a semiconductor with an extended extrinsic regime below 200 K and a band gap of about 0.4 eV at room temperature. The subchlorides are diamagnetic at room temperature though a paramagnetic contribution appears towards lower temperature. Below 40 K, both compounds pass through a magnetic ordering that shows a hysteresis curve in the magnetization.