I request you to kindly suggest me some latest input/output expanders. so that I could control number of led's with lesser number of chips.

are you sure?
Multiplexing is fine if you are making a totally static display, it will give you headache upon headache if you want to do things like scroll. Also, intensity control becomes quite tricky. You will find out that the 'housekeeping' takes so much processor power that you most likely will need a faster processor and for scrolling color, I am using the fastest availabale without multiplexing,

I do not see the value of spending $5 on multiplexing components to save $6 on the number of drivers. YES, this DOES represent the ratio I found last I investigated.

You will need higher current capabilty from your column drivesr that from the non-multiplexed drivers (= higher cost per driver) you will need very high current row selectors (= added cost) and, in the end you will end up with a perfect EMI generator.

My business being signs (we use 1.000.000+ LEDs every month) I have, after lots of research, concluded that if a sign is to do AMYTHING more than show a static message multiplexing is out. Of course, if you are making displays where the apopearance quality is irrelevant, that is another issue.

In my, well founded, opinion there is no way to make a high quality display other than individual constant current drivers (such as Siti ST2221, Rohm offerings, Allegro offerings)

We are currently investigating the Allegro A6279 which promises a greatly reduced EMI by a slight lag between the ON times.

Erik