handling of time durations

my format in column A will be like this :

Thu 08/08/2013 10:35
Fri 09/08/2013 12:01
Sat 10/08/2013 07:04
Sun 11/08/2013 13:10
Thu 12/09/2013 18:15
Tue 13/08/2013 16:09
Wed 14/08/2013 16:19
Sun 15/12/2013 11:04
Fri 16/08/2013 10:37

Try this in C2.

=IF(AND(B2>=TIMEVALUE("10:34:00"))*(B2<=TIMEVALUE("12:00:00")),"Phase1",IF(AND(B2>=TIMEVALUE("12:00:00"))*(B2<=TIMEVALUE("15:10:00")),"Phase2",IF(AND(B2>=TIMEVALUE("15:11:00"))*(B2<=TIMEVALUE("16:10:00")),"Phase3",IF(AND(B2>=TIMEVALUE("16:11:00"))*(B2<=TIMEVALUE("18:10:00")),"Phase4",""))))

thanks for your reply; now i have scenario for time overlap ; if the student came to my school in the below timings ; phase need to print accordingly;

Student Visiting to the the Class if Timings : In between 10:35 to 12:00 ; Phase 1 should print in Column B.

Student Visiting to the the Class if Timings : In between 11:49 to 15:10 ; Phase 2 should print in Column B.

Student Visiting to the the Class if Timings : In between 14:11 to 16:10 ; Phase 3 should print in Column B.

Student Visiting to the the Class if Timings : In between 15:20 to 18:10 ; Phase 4 should print in Column B.

I don't think you can do it because you will have conflicts where the times overlap. You can't have a statement that says if the time is greater than 11:49 and less than 15:10 that = Phase2 if you have another statement in the same sum where 14:11 (which is less that 15:10) is part of the statement for Phase 3.

You will have to split the calculation up and spread it across several columns. (I think).