It was the premises of the famous Earley & Company stained glass artists, docjohnoscar. They moved in around 1900, when the delightful commercialising niche was inserted at ground floor level - hence also the circular window with stained glass. There's also a church out the back, which if I recall, along with the houses, was to be mauled/compromised as part of an insane development proposal as jdivision mentions above. Indeed it may well have been the intention to demolish the church - I can't remember. The owners are, shall we say, well known for their refined patronage of matters architectural.
The Camden Court Hotel is a great spot for basing youself on a visit to Dublin it has to be said. In addition to their fantastic breakfasts, you walk straight out the door into the most dynamic quarter of the city, with all the vibrancy of Camden Street, the amenities of the Iveagh Gardens and St. Stephen's Green, the ease of access to the south Georgian core, and the lovely summer morning walks around the gracious residential streets of Portobello. Definitely a spot worth recommending to visiting relatives, if they can endure the tribute to 90s faux mahogany that are the bedrooms.