Since 1998 he had been actively involved into volunteering with Belarusian office of Service Civil International (SCI), from 2000 till 2003 he was a member of the Financial Councilors Committee of this organization.
After graduation he was working in Priorbank (part of Raiffeisen Holding, Austria), then shifting to IT business and realization of the Fostering Opportunities in Belarusian Green Movement project.
In the same year Marozau established and took charge of the Valgevene Uus Tee civic organization in Tallinn (Estonia), which aims to develop critical thinking skills of young people in the post-Soviet countries and carries out multiple cultural and media projects in the Baltics, Belarus, Ukraine and Russia.
In late 2014 Marozau founded Russian-language web television ARU TV aimed to counteract Kremlin propaganda in Eastern Europe.
In addition, he is the organizer of the RUBYCON annual conference for Russian and Belarusian pro-democratic experts and journalists conducted in partnership with the Estonian MFA.