In this work we use ab initio density functional theory (DFT) and propose three new configurations of substituted graphene monolayers where the carbon atoms are replaced selectively by boron and nitrogen. The stable equilibrium geometries and corresponding structural, electronic and transport properties of the resulting graphene-like BC, NC and BN hexagonal single-atomic-layer compounds are determined. The characteristics of the NC and BC new compounds are found to be metallic. Our proposed boron-nitrogen hexagonal structure behaves as a semiconductor with gap of 0.52 eV, while the h-BN (alternating boron and nitrogen in graphene structure) studied so far widely is typically an insulator or a wide-band semiconductor. The value of electric current in BC structure is found to be higher than that in usual graphene for a given value of the bias voltage. (C) 2017 Elsevier B. V. All rights reserved.