$SbS_{1-x}Se_xI,;BiS_{1-x}Se_xI,;Sb_{1-x}Bi_xSI,;Sb_{1-x}Bi_xSeI,;SbS_{1-x}Se_xI:Co,;BiS_{1-x}Se_xI:Co,;Sb_{1-x}Bi_xSI:Co$, and $Sb_{1-x}Bi_xSeI:Co$ single crystals were grown by the vertical Bridgman method using the ingots. It has been found that these single crystals have an orthorhombic structure and indirect optical transition. The composition dependences of energy gaps are given by $E_g(x)=E_g(0)-Ax+Bx^2$. The impurity optical absorption peaks due to cobalt deped with impurity are attributed to the electron transitions between the split energy levels of $Co^{2+}$ and $Co^{3+}$ ions sited at $T_d$symmetry of the host lattice.