We investigated a suspended bilayer graphene where the bottom (top) layer is doped by boron (nitrogen) substitutional atoms by using Density Functional Theory (DFT) calculations. We found that at high dopant concentration (one B-N pair every 32 C atoms) the electronic structure of the bilayer does not depend on the B-N distance but on the relative occupation of the bilayer graphene sub-lattices by B and N. We found that a large built in electric field is established between layers, giving rise to an energy gap. We further investigated the transport properties and found that intra-layer electron current is weakly influenced by the presence of these dopants while the inter-layer current is significantly enhanced for biases allowing the energy alignment of N and B states. This effect leads to current rectification in asymmetric junctions.