I owned a domain name BankOfCityName.com, where CityName is the name of a big city. But recently a big bank changed its name to Bank Of CityName, my question is:
what kind of website should I build now to avoid the IP infringement?
There are a few more questions you should be asking yourself.
1) Did you "just happen" to register Bank of CITY, or did you read a press announcement that Bank of WORD was changing to Bank of CITY?
2) Did you not see such an announcement, yet upon further research, it appears that one was issued?
If either of those questions can be answered affirmatively, you may have a bigger challenge ahead of you than you think.
Two cases dealing with that issue, with different results:
http://www.wipo.int/amc/en/domains/decisions/html/2007/d2007-1782.html
http://www.wipo.int/amc/en/domains/decisions/html/2009/d2009-0041.html
The difference? Both domainers clearly decided to capitalize on announcements of new business ventures. However, the first one also decided to hire a competent lawyer. The second one hired a really bad lawyer (himself).
The best thing you can do for yourself at this point is to get all your documents together that might support your position that the answer to both of the questions above is a resounding "no." Being able to prove that you registered the domain name without any actual knowledge of the bank's plans will help. But, panels (correctly so) also charge registrants with "constructive knowledge." In other words, if you had to have known or just tried to remain willfully ignorant, then you don't get rewarded for your voluntary ignorance.
So figure out when you acquired the domain (easy).
Then, figure out when the bank made its first public announcement of any kind that it might be changing its name. If that date is after your date of acquisition, this will really help you. If not, you're going to have a greater challenge defending the domain, no matter what content you use.