Optical and thermal properties of metal organic chemical vapor deposition (MOCVD) grown BGaAs/GaAs alloys with boron composition of 3% and 8% are investigated by photothermal deflection spectroscopy (PDS). The band gap energy, absorption spectrum and thermal conductivities are evaluated by comparing the experimental and the theoretical PDS signals amplitude and phase. The boron effects in these parameters have been shown. In fact, it was found that gap energy and thermal conductivity of BGaAs/GaAs alloys with 3% of boron are respectivelly 1376 mev and 4.7 W/m K, these values decrease to 1360 mev and 3.5 W/m K for 8% of boron composition. (c) 2012 Elsevier B.V. All rights reserved.