Christianna Diogenous holds a B.Sc. in Social Psychology from the London School of Economics in the United Kingdom and MBA from INSEAD Business School. After studying, she worked as a Management Consultant at PriceWaterhouseCoopers in the United Kingdom. On her return to Cyprus she joined the PM Tseriotis Group and reorganized the Human Resources Department, which she headed until 2004. At the same time, she was involved in the Marketing and Public Relations of the Group. In 2004 she was appointed Marketing Manager of Unicars and in 2005 became Marketing Director of the same company. In mid-2007 she moved to Tseriotis Consumer Goods, taking over as Managing Director. She then became Chief Executive Officer of Diapo Ltd, a 3PL company developed by Tseriotis Consumer Goods. In 2012, she played a leading role in setting up Unilever Tseriotis Cyprus as well as in the merger that created Tryfon Tseriotis Ltd.
In 2017 she returned to Unicars to become CEO.
She is a member of the Board of Directors of PM Tseriotis and holds a position of the Board of Directors in all the companies under the Group. She is also a member of the Board of Directors of the Association of Motor Vehicle Importers and the Navy Club of Nicosia.