This building is Viharn Yod, erected by King Rama III. Its super structure is in the form of a Thai crown ornamented with multi-coloured pieces of glazed terracotta. The mother-of-pearl inlaid door of this structure dates back to the late Ayutthaya period. Inside are kept some Buddha images.
The building on your right is Ho Phra Monthien Tham, the supplementary Library, Annex regarded as an auxiliary scripture hall, housing the rest of the Tripitaka. It was also used as a site for the translation of foreign correspondence.
That building on your left is Ho Phra Nak. It was constructed to house a large standing Buddha image of copper alloy named Phra Nak. The image had been moved down from Ayutthaya and now is kept in the Viharn Yod, but the name of Ho Phra Nak still remains. Inside the building are kept some ashes of members of the royal family.