Executive Assistant

Executive Assistant San Leandro, California, United States SirenOpt helps manufacturers make better, safer, and more reliable micro- and nano-materials. These materials are the building blocks of critical sectors of the global economy such as batteries, computer chips, aircraft components, and power systems. But, surging material demand and growing complexity are pushing production to unprecedented scales and speeds, leaving manufacturers effectively flying blind. Small, undetected variations during production lead to wastage, lower performance, higher costs, and safety risks. SirenOpt is changing this. Our manufacturing intelligence platform scans materials, revealing critical internal information without damaging them. Using a novel combination of cold atmospheric plasma, physics-informed machine learning, and predictive analytics, SirenOpt creates unique, real-time fingerprints that capture material signals no other method can access. These insights give manufacturers unprecedented visibility into how materials behave as they are made. We turn hidden data into actionable intelligence to help manufacturers reduce variability and thus increase yield and performance. The technology can be deployed as a standalone tool or integrated directly into factory production lines. SirenOpt is currently deploying early versions of its platform with some of the largest industrial manufacturers in the world across North America, Europe, and Asia. Our first commercial product will be released in 2026. Role Overview SirenOpt is looking for an Executive Assistant to support our leadership team and the broader company. This is a company-wide role you will work across functions to ensure our leaders and teams can operate efficiently and effectively with clear communication, organization, and scheduling. You will serve as a central operational resource for the organization. A majority of your time will be dedicated to supporting key individuals including the CEO and other leaders with scheduling, communications, and administrative tasks; the remainder will consist of providing general company-wide administrative support. What You'll Do Manage complex calendars and scheduling for key company leaders coordinating across time zones and competing priorities with speed and good judgment Arrange domestic and international travel, including flights, hotels, ground transportation, and itinerary logistics Support executive communications drafting, formatting, and organizing emails, meeting agendas, follow-ups, and recaps Coordinate meetings and events, including customer visits, internal team offsites, and other logistical activities Manage expense reporting and reconciliation using Expensify and Brex Maintain shared documents, files, and records in Microsoft 365 and Confluence Handle general office and corporate administrative functions vendor coordination, office supplies, onboarding logistics, and other operational needs as they arise Field ad hoc requests from across the company and act as a reliable resource for teams that need administrative support What We're Looking For Bachelor's degree or equivalent 36 years of experience in an administrative or executive assistant role, ideally supporting multiple principals simultaneously Demonstrated ability to manage competing priorities across different leaders or departments including an adept understanding of how to triage, escalate when needed, and stay ahead of problems Experience in a startup or fast-moving environment where processes are still being developed and implemented Strong organizational skills and attention to detail Strong written communication skills; able to draft professional correspondence on behalf of executives Proactive and able to anticipate needs before being asked and take initiative without waiting for direction when needed Proficient with Microsoft 365 (Outlook, Word, Excel, Teams) and comfortable picking up new tools quickly; familiarity with Confluence, Expensify, Brex, and HubSpot is a plus Discretion and good judgment when handling sensitive information Why Join SirenOpt Opportunity to make a direct impact in building a growing, mission-driven company Work closely with leadership and drive company organization and communication Fast-paced, collaborative startup environment with high ownership Exposure to cutting-edge technology in advanced manufacturing and AI Base Pay Range $75,000 - $95,000 USD Benefits Equity and salary compensation depends on experience Health, dental, vision plans provided 401k matching provided Time off: 20 days of PTO per year, plus approximately 15 paid US holidays per year