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Less than five years after real estate executive MaryAnne Gilmartin founded her own firm, MAG Partners, and a little over a year after leasing launched at Ruby, its first ground-up project, this amenity-rich, biophilic project has reached 85% leased. However, the woman-owned real estate firm has not rested on its laurels but stayed rather busy: Construction has topped out on not one but two forthcoming projects, 335 Eighth Avenue in Chelsea and 300 East 50th Street in Turtle Bay, on the same day.
Just as Ruby was named in honor of acclaimed fashion designer Ruby Bailey, these projects are expected to be named after influential women. These will be announced at a later date, and leasing on both projects will likely commence in 2025. In the meantime, we take a look at the forthcoming buildings that are set to bring nearly 400 units of mixed-income housing to Manhattan.

In this article:

335 Eighth Avenue
335 Eighth Avenue Chelsea
300 East 50th Street
300 East 50th Street Turtle Bay/United Nations
MaryAnne Gilmartin speaking at 335 Eighth Avenue topping out ceremony MAG Partners founder MaryAnne Gilmartin speaking at ceremony (Michael Young)

300 East 50th Street, Turtle Bay
Developed in partnership with Safanad and Global Holdings | Design by BKSK Architects
23 stories | 194 units

300 East 30th Street, new rental tower Rendering of 300 East 50th Street (BKSK Architects) | Photo taken late May 2024 (CityRealty)
50th Street Team - Danny Jumblatt, JJ Ofer, MaryAnne Gilmartin, Andy D_Amico, Todd Poisson, Kevin Wang, Reggie Kronstadt
300 East 50th Street is taking shape on the southeast corner of Second Avenue and East 50th Street, where it will make a dramatic statement between its towering height, detailed masonry, neutral-toned facade, and setbacks of varying heights. Permits indicate that there will be between ten to twelve apartments per floor on levels 2-15, and only five to seven apartments per floor on levels 16-23. The project also calls for five new trees to be planted on the two street frontages.

As footings were laid just before the 421a tax abatement program expired in June 2022, 300 East 50th Street qualifies for the benefits and has designated 30% of the units inside as permanently affordable. All residents will enjoy access to amenities like a fitness center, a lounge, a bike room, a courtyard, and a roof deck.
300 East 50th Street progress
Construction shot of 300 East 50th Street 300 East 50th Street, late May 2024 (CityRealty)
300 East 50th Street rising into the Turtle Bay-Midtown East skyline

335 Eighth Avenue, Chelsea
Developed in partnership with Safanad and MetLife Investment Management | Design by COOKFOX
7 stories | 188 units

335 Eighth Avenue building Rendering of 335 Eighth Avenue (COOKFOX)
Eighth Avenue Team - Ryan Dziedziech, Sara Queen, Andy D’Amico, MaryAnne Gilmartin, Ambur Nicosia, Danny Jumblatt, Rick Cook (Photo: Michael Young)
Just up the street from Ruby, MAG Partners has reunited with that project's designer to replace the aging Penn South affordable housing cooperative with a new building designed to Passive House and LEED Gold certifications. COOKFOX is known for its biophilic designs, and founder Rick Cook describes the project as “wellness-focused, nature-connected residences for a diverse new community.” Renderings depict a modern take on historic Chelsea character.

Just like at 300 East 50th Street, 30% of units at 335 Eighth Avenue have been reserved for low- and middle-income New Yorkers. In addition to the new housing units, the project will bring new commercial space to this stretch of Chelsea just south of Penn Station, including a 23,000-square-foot Lidl supermarket. Moreover, at the topping-out ceremony, MAG Partners unveiled "Panoramica," an original painting by Penn South resident Joseph Meloy that will hang on the fence for the duration of construction.
335 Eighth Avenue The building should be larger given its central location, but the 5,000 neighbors in the surrounding Penn South co-ops preferred this low-rise massing. These north Chelsea blocks are an odd pocket of mid-century planning but provide much alleviation from surrounding high-density districts.
335 Eighth Avenue construction progress 335 Eighth Avenue, late May 2024 (CityRealty)
Rendering via COOKFOX Architects