The new firm will retain the Leader Communications name; Immediate boss Geraldine Sheridan will assume the title of director under Leader chief executive James Holden.
Last year Leader billed just less than £600,000, and chief executive James Holden said he hoped the merger would push this figure 'closer to the £1m mark' in the next 12 months.
Leader currently works across consumer, B2B, events and not-for-profit sectors, and handles exhibitions, including the global Snow Show. Its consumer clients include the Midlands arm of Greggs and Blenheim Palace, but Holden said Immediate's experience in the retail sector would provide a boost for the merged firm's consumer team.
'Immediate's work in consumer retail will be very useful, and Geraldine also brings excellent business development skills,' said Holden. 'Her ability to win new clients will be a real catalyst for the growth of the merged firm.'