The structural, magnetic and optical properties of Rh2MnAl and Rh2MnBi Heusler alloys have been studied through the full potential linearized augmented plane wave (FP-LAPW) method. The exchange-correlation potential was treated within the generalized gradient approximation (GGA). The effect of the magnetic ordering, i.e. ferromagnetic (FM) and antiferromangnetic (AFM) along [001] and [111] crystal axis on the dielectric functions is revealed. Our calculations show that the Kerr rotation and elipticity is enhanced within 0-8 eV energy range by the substitution of Al by semimet al. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim