We report a thermal transport study of IrSbSe, which crystallizes in noncentrosymmetric cubic structure with the $P{2}_{1}3$ space group and shows narrow-gap semiconducting behavior. The large discrepancy between activation energy for conductivity [${E}_{\ensuremath{\rho}}=128(2)$ meV] thermopower [${E}_{S}=17.7(9)$ from 200 to 300 K indicates polaronic mechanism. electrical resistivity varies ...