A company that is opening a medical-marijuana dispensary in East Boston said it has a purchase-and-sale agreement to buy BC dive Mary Ann's on Beacon Street and rebuild the decrepit place into a contemporary pot shop serving both recreational and medical marijuana users.

Not so fast, a number of people warned Happy Valley Ventures of Massachusetts at a meeting of the Brighton Allston Improvement Association Wednesday night, at which they raised the specter of hordes of pot-seeking BC students descending on the shop and scaring off families from Cleveland Circle.

George Haivanis, owner of Reservoir Wines and Liquors, said he and other merchants have spent long years working to improve Cleveland Circle and they're not about to let a pot shop ruin that. "Cleveland Circle is a place for families to come with kids to walk and eat," and swim in the DCR pool, not a place for people to load up on pot, he said.

He gave BAIA officials letters from ten Cleveland Circle merchants also opposed to the proposal - and said more of them would have attended the meeting had they not heard about the agenda at the last minute. Turning to Happy Valley officials and their lawyer, he warned, "We're not going away."

Before it can open, Happy Valley would need to win a letter of "non opposition" from the City Council and approval from both state marijuana regulators and the Boston zoning board.

Happy Valley COO and founder Michael Reardon and two other Happy Valley officials said their goal is to create a facility similar to a doctor's office or pharmacy, where customers would have to show ID at four separate points before being allowed to walk out with any marijuana products. Recreational users would be limited to an ounce of "flower" or 8 grams of marijuana concentrate - at prices high enough to discourage them from trying to re-sell it on the street.

Reardon and Happy Valley attorney Jeff Drago said the store would be a vast improvement over Mary Ann's - it would close at 9 p.m. rather than 2 a.m. and residents would have one fewer local source of loud students infused with cheap drinks. It would have a capacity of 47 people at a time - eight of them employees - unlike Mary Ann's, which has a licensed capacity of 200. The company says it would use both security guards and cameras to ensure customers did not loiter in the area.

And, they said, the facility would have a large waiting room - so that customers would be inside rather than queuing up outside. That alone was a must for association Vice President Anabela Gomes, who pointed to the lines stretching along Rte. 9 outside a dispensary in Brookline Village. Reardon also reassured her the signage would be low-key and that even if he wanted to, he couldn't hire what she called "people dressed up like pot leaves" waving people in, because, unlike in anything-goes California, that's illegal in Massachusetts.

Proposed waiting room - note absence of sticky floors:

But all the reassurances were not enough for Bill Mills, director of community affairs at Boston College, who said a pot shop within an easy walk of 9,200 BC students is just not a good idea, especially in an area on the upswing - just look, he said, at the new hotel and senior apartments nearing completion on Chestnut Hill Avenue. A pot shop "is just not an improvement to the area," he said.

He added that the only reason that Bill Evans, BC's police chief and former Boston police commissioner, did not attend was because of a prior commitment in Newton. An officer from BPD's District D-14 did attend and said the department opposes a marijuana shop in Cleveland Circle.

Mills even questioned whether Mary Ann's was really so bad. Sure, it pissed the neighborhood off for several decades, but the bar shaped up after it was chewed out by the Boston Licensing Board three years ago and had turned into a good, if shabby, neighbor, he said.

If it can win approval, Happy Valley would buy the building from a group headed by principals at City Realty - which in turn had purchased the bar, and some other Boston dives - earlier this year.

At a licensing-board hearing in July, the group said it planned to keep Mary Ann's pretty much the same. But at tonight's BAIA meeting, a City Realty official said his bosses readily agreed to the proposed Happy Valley deal because "we're developers" who aren't really in the business of running bars.

The proposal did have a couple of supporters, who agreed that it would represent a major enhancement to the area over Mary Ann's, that area students in pursuit of pot are already getting it and that Boston residents voted overwhelmingly to legalize marijuana. One resident, though, disputed that, saying legalization won only because large numbers of students registered to vote specifically for marijuana.