CIU's main asset is an uncompleted four-star hotel in Shenzen, south China.
Stonehill also aims to raise pounds 4.2m through a two-for-one rights issue at 10p. The issue is conditional on the completion of the CIU deal.
Payment for CIU, whose 346- room Landmark Hotel is expected to open in June, will be in the form of 517m 'A' Stonehill shares at 10p. The pounds 51.7m consideration matches the reported net assets of CIU.
Shares in Stonehill, which owns 20 acres on the Lea Valley trading estate, were suspended at 11p on 5 January.
To conform with takeover rules, CIU, which promises that 25 per cent of Stonehill will remain in public hands, plans to make a general offer at 10p. Stonehill's directors are recommending shareholders not to accept.
Stonehill's existing shareholders will be diluted to only 4 per cent of the enlarged group before the rights issue.
The new-look Stonehill plans to acquire and develop more properties and to take equity stakes in property companies or companies with substantial property interests in China. Wu Zhen-tao, Richard Wong and Stephen Hunt, directors of CIU, will be invited to join the board of Stonehill. Mr Wu, who owns CUI's parent, Cathay International Investment, will become chief executive.
Stonehill is currently controlled by a consortium of investors following a deal in September 1987 led by James Buchanan, chairman, and Tranwood Earl, a now- defunct finance house.
The company has consistently lost money apart from a one-off pounds 2m property profit on Elstree film studios in 1989.
It has not paid a dividend since 1986 and by last September had run up debts of pounds 12.5m against a reported net worth of pounds 5.9m.