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b12 Labs

YC S25

San Francisco, US · Founded 2025 · 3 employees · Hiring · 9 known investors

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b12 develops AI agents and lab automation software to help chemists plan, optimize, and execute the synthesis of complex molecules. The platform combines chemistry expertise with agentic AI systems to streamline organic synthesis workflows.

Also known as b-12, Co. · b-12 · B12 · B12, b-12

AI & Machine LearningBiotechDeep TechEnterprise SoftwareHealthtechRoboticsAI-powered Drug DiscoveryUnited States of AmericaAmerica / Canada

Founders & leadership· Y Combinator alumni (S25)

b12 Labs was founded in 2025 by Zlatko Jončev and Andres Bran.

ZJZlatko Jončev
Zlatko JončevCEOZlatko Jončev completed a postdoctoral fellowship at EPFL's Lab of Artificial Chemical Intelligence, where he met co-founder Andres. He is developing AI agents to automate workflows in chemistry and pharmaceutical R&D.
ABAndres Bran
Andres BranCTOAndres developed AI agents for molecular design and planning in robotic laboratory settings, with published research in machine learning applied to chemistry. He completed a PhD at EPFL in AI and chemistry, and previously interned at the Max Planck Institute.
AF
Adriana FaraoneResearch Scientist

Investors · 9

Transpose Platform Managementlisted by Transpose Platform ManagementSan Francisco

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ZAKA VClisted by ZAKA VCSan Francisco

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C Square Capitalreported

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MyAsiaVCreportedSeattle

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OurCrowdreportedJerusalem

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Tekedia CapitalreportedLagos · $1K

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Twenty Two VenturesreportedPalo Alto · $50K – $250K

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WefunderreportedSan Francisco

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The YC application· Summer 2025 batch

Alumni Q&A

How did your company get started? (i.e., How did the founders meet? How did you come up with the idea? How did you decide to be a founder?)
The founders, Andres and Zlatko, met at EPFL in the Lab of Artificial Chemical Intelligence, where Zlatko was a postdoc and Andres was a PhD student.
How did you decide to apply to Y Combinator? What was your experience applying, going through the batch, and fundraising at demo day?
The founders applied after YC partners visited their campus at EPFL, and described the batch as demanding but a source of useful advice on building a startup.

Summarized from the founders' answers on their Y Combinator profile.

Images

b12 Labs photo

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Companies working in the same space as b12 Labs.

Legal entities · 1

corporate structure
b-12, Co.

In the news

b-12 - Chemistry Copilot for Pharma & Biotechycombinator.com · Jul 2025

Frequently asked questions

What does b12 Labs do?
b12 develops AI agents and lab automation software to help chemists plan, optimize, and execute the synthesis of complex molecules. The platform combines chemistry expertise with agentic AI systems to streamline organic synthesis workflows.
Who founded b12 Labs?
b12 Labs was founded by Zlatko Jončev, Andres Bran in 2025.
Who are b12 Labs's investors?
b12 Labs's investors include Y Combinator, Transpose Platform Management, ZAKA VC, C Square Capital, MyAsiaVC, OurCrowd, Tekedia Capital, Twenty Two Ventures and 1 more.
Where is b12 Labs headquartered?
b12 Labs is headquartered in San Francisco, US.