A very thin layer of hexagonal boron nitride (h-BN) is an important 2D nanomaterial, sometimes called ‘white graphene’, with many properties distinct from graphene. However, the lack of controlled synthesis of high quality and wide-area films largely prevents realisation of the full potential of this material. In this review article, a comprehensive overview of the current status of the synthesis, growth mechanism using chemical vapour deposition, structure and electronic properties to tune the bandgap is covered. In particular, the progress towards achieving the improved quality and functionalities of the h-BN films via epitaxial growth and control of grain size, number of layers, morphology and orientation have been critically reviewed. In addition to synthesis and properties of the atomically thin (mono and few layer) h-BN, the applications in possible and emerging areas are also described and discussed.