Hybridized　two-dimensional　materials　incorporating　domains　from　the　hexagonal　boron　nitride　(h-BN)　and　graphene　is　an　interesting　branch　of　materials　science　due　to　their　highly　tunable　electronic　properties.　In　the　present　study,　we　investigate　the　hydrogenated　two-dimensional　(2D)　h-BN/C　superlattices　(SLs)　with　zigzag　edges　using　first-principles　calculations.　We　found　that　the　domain　width,　the　phase　ratio,　and　the　vertical　dipole　orientation　all　have　significant　influence　on　the　stability　of　SLs.　The　electronic　reconstruction　is　associated　with　the　lateral　polar　discontinuities　at　the　zigzag　edges　and　the　vertically　polarized　(B2N2H4)(m)　domains,　which　modifies　the　electronic　structures　and　the　spatial　potential　of　the　SLs　significantly.　Furthermore,　we　demonstrate　that　the　hydrogenated　2D　h-BN/C　SLs　can　be　applied　in　engineering　the　electronic　structure　of　graphene:　laterally-varying　doping　can　be　achieved　by　taking　advantage　of　the　spatial　variation　of　the　surface　potential　of　the　SLs.　By　applying　an　external　vertical　electric　field　on　these　novel　bidirectional　heterostructures,　graphene　doping　levels　and　band　offsets　can　be　tuned　to　a　wide　range,　such　that　the　graphene　doping　profile　can　be　switched　from　the　bipolar　(p-n　junction)　to　unipolar　(n(+)-n　junction)　mode.　It　is　expected　that　such　bidirectional　heterostructures　provide　an　effective　approach　for　developing　novel　nanoscale　electronic　devices　and　improving　our　understanding　of　the　fundamentals　of　low-dimensional　materials.