I did some quick research on Frank Dupee. First, according to Illustrated Boston, the metropolis of New England. 1889, there was a Frank Dupee at 185 Summer Street that was a wool trader.

I also called Boston Public Library Kirstein Business Library and they did not have a listing for him as a coin and stamp dealer. One last thing he could have been is the third-worst pitcher in the history of major league baseball.... but because he needs good eyesight to be a coin dealer in the era before loupes this might be a dead lead...

Regarding Frank Dupee, I have not yet found anything on him. Looking at the post card photograph a coin parking meter is seen at the curb in front of the store. The first parking meters were installed in the summer of 1935 in Oklahoma City. The parking meter in the photograph does not look new, but perhaps, about a decade or more old. I am not sure, but it does look like it might be either a MI-CO or Rockwell Meter single head model from the 1940's. Perhaps someone expert on this can identify it better. I am not sure when Boston installed the first parking meters but they did install 5,000 in May 1948. My guess is that the post card dates from the late 1940's to late 1950's.

Also in view in the photograph is a car parked on the corner, which seems to corroborate this dating. If the backside of the post card is shown it might offer additional clues about the dating, especially the name of the printer, or if a postage stamp is franked, or any postal cancellation markings. Consequently, I doubt that Frank Dupee, the stamp and coin dealer, is identical to the man with the same name, who, donated money in 1909, since he would be in his mid to late 70's or 80's at the time of the photograph.

It is hard to tell where the store is located from the photograph but the cityscape reflected on the glass storefront window shows one lonely skyscraper, most probably an office building, rather than tenement housing.

I am not sure about the cityscape of Boston's North End section during this time-frame if in fact it matches that of the window reflection in this photograph. Perhaps someone from the Boston Historical Society can help. Hopefully someone has better data to inform us whether or not David Ganz's kind suggestions are right regarding the identification of the man and location of his store.

About Frank Dupee, never heard of him, but, he's not from that long ago, see the parking meter on the sidewalk in the picture. Checking the Social Security Death Index, a good place to start a search, I see several Frank Dupees, three of whom had their SS numbers issued in Connecticut. I don't know though, the image of the city, reflected in his front window, could well be Boston...

As a youngster I used to frequent the Frank Dupee Stamp & Coin shop in New Haven, Connecticut with my grandfather, an avid stamp collector. From what I remember, his business was almost all stamps, with just one corner of the shop dedicated to coins, but then again, my memory isn't what it used to be either!

I'm not having any luck with New Haven directories...do you think he might have advertised in The Numismatist?

Real Photo Post Cards have become quite a big field in collecting. I have friends who go into that in detail. There are a number of Fricke Differences (subtle variations, named for a local collector) in the details that can date them. If you send an image of the back of the card I could probably have it dated as closely as is possible. It would take some checking, and I would learn more about this field in the process. EK Co. produced Photo Post Card stock for decades, and I still have some unexposed sheets in a box in our collection. I'd guess from 1910 through 2005 era without checking.