Team

Staff

• Sammy Politziner

  Co-Founder

  

  Sammy graduated from the University of Michigan and moved to New York City, where he taught second grade in the South Bronx with Teach for America and founded a small academic summer camp for his students.  After a stint of world traveling, Sammy moved north for a master’s degree from the Harvard Graduate School of Education and then down south to teach at a KIPP school in North Carolina.  Sammy returned to New York for a job in investment banking at Kildare Capital, a boutique firm, where he spent five years providing sell-side M&A and capital formation advice.

  When not co-leading Arbor Rising, Sammy often dreams of starting a family band, running marathons in faraway lands and Michigan football winning the national championship (or at least reliving the glorious recent victories over Ohio State again and again).

• Scott Thomas

  Co-Founder

  

  Scott earned an engineering degree from the University of Michigan, which he promptly misplaced and came to work as a middle school mathematics instructor through Teach for America in NYC’s Washington Heights neighborhood.  After another left turn to collect an MBA from NYU, Scott joined Lehman Brothers and later Neuberger Berman, where he helped manage investments in infrastructure and alternative energy companies.  Feeling the call to unite the social justice and business aspects of his career, he co-founded Arbor Brothers (now Arbor Rising) with Sammy in 2010 and continues to co-lead it today.

  Scott is grateful to serve on the board of Summer Search, a national youth development organization.  He has had the opportunity to guest lecture at Harvard, Columbia & NYU and is a member of the Leap Ambassadors Community.  When he’s not in the office he can be found chasing his Tasmanian-devil children and dog through the parks of Brooklyn.

• Rebecca Cullen

  Principal

  

  Prior to joining Arbor Rising in 2020, Rebecca served as the President at College Advising Corps, a national college access organization, where she oversaw a $45M budget and led 50+ staff members to increase opportunity annually for 200,000+ low-income, first-generation, underrepresented students. Before College Advising Corps, Rebecca fostered her passion for social justice at the Jack Kent Cooke Foundation where she spent more than a decade developing scholarship programs to advance the education of high-achieving, low-income students across the country. Earlier in her career, Rebecca managed an after-school learning center at Kaplan, worked in independent school admissions, coached refugees to find employment, and taught English in Russia.

  Rebecca earned her BA in history at Georgetown University. She enjoys travel, yoga, walking, tennis, and singing.

• Rochelle Sinclair

  Principal

  

  With a bachelor’s degree from New York University and an MBA from the University of Michigan, Rochelle began her career as a strategy consultant with PricewaterhouseCoopers (PwC) assisting clients through mergers, acquisitions, and growth through innovation. Fueled by her passion for equity and liberation, she transitioned to social impact work through a fellowship with The Broad Residency in Urban Education. Over the years, Rochelle has launched a statewide school improvement initiative at the New Jersey Department of Education and designed a teacher development program at Harlem Village Academies.  Most recently, Rochelle served as the Executive Director in New York for OneGoal, where she led her regional team towards increasing access, opportunity, and postsecondary completion rates for thousands of students across NYC.

  Rochelle joined Arbor Rising in 2023. She enjoys cooking in her free time and singing and cuddling with her kids at all times.

• Courtney Tran

  Engagement Manager

  

  Courtney’s interest in social impact work began in California, where she served on the Oakland Public Library’s Youth Leadership Council, volunteered with the Berkeley Anti-Trafficking Coalition and supported research into social determinants of health in America. After graduating from UC Berkeley, Courtney moved to New York to complete a fellowship at Human Rights Watch, where she investigated attacks on medical facilities in conflict zones. She then completed an international development fellowship with the International Innovation Corps and the Self-Employed Women’s Association in India before returning to New York to earn a Master’s in International Affairs at Columbia University.

  Courtney joined Arbor Rising in 2020. In addition to her human rights and development background, she has nine years of private teaching and tutoring experience.

   

• Melanie Jiménez

  Senior Associate

  

  After receiving a bachelor’s degree from UC Berkeley in 2016, Melanie spent a year as a research fellow at a Policy organization in Oakland, CA. In Oakland, she developed a strong interest in community impact and over the next 5 years, she applied this interest through a philanthropic lens at San Francisco Foundation (SFF). Through partnering with organizations and fellow funders, Melanie better understood what community impact could look like at a local level through relationship-building and strategic funding. During her years at SFF, she became the Program lead for the Foundation’s Program Related Investments and oversaw multiple grantmaking portfolios focused on anti-displacement efforts and community wealth-building through collective ownership over land, housing, and business. She then moved to the East Coast and pursued her Master’s in Social Policy from the University of Pennsylvania.

  Melanie joined Arbor Rising as a Senior Associate in 2022.

• Caroline Ostrover

  Senior Associate

  

  Caroline graduated from Yale University in 2017 with a BA in American Studies. Her passion for youth development began in New Haven, where she worked as a volunteer tutor at New Haven Reads. After graduating, Caroline spent three years working as an art advisor at Sotheby’s and Murphy & Partners in New York City. She then earned a Master’s in Business Administration from Columbia University. During this time, she served as a member of the Nonprofit Board Leadership Program and the Harlem Tutorial Program. She gained further experience working to provide youth with meaningful opportunity as a Business Development intern with Juma Ventures.

  Caroline joined Arbor Rising as a Senior Associate in 2022. She is passionate about the outdoors, art, reading fiction, and college football.