To my surprise, I've found another automobile manufacturer in Jamaica Plain. Earlier entries have been American Napier and Farnham Nelson. The Lenox Motor Car company was the successor to the Martell Motor Car company. There is very little available on the company, but they seem to have begun in 1911 in brick buildings erected and owned by local real estate mogul Patrick Meehan on Washington street near the corner of Glen road (the address was that of the long building on the right above with the name Meehan across it). In 1915, they moved to Lawrence, and in doing so bankrupted themselves. The building they began in is still there today.
Source: The Lenox Motor Car Company