This is about the day I visited 4 museums. This is a full day so pace yourself. Start out with the Istanbul Modern museum, this should take about 3 or 4 hours and next cross the road and head up the hill to the Tophane Arsenal, which is a building designed by Mimar Sinan in the 15th century and has been turned into an art gallery by the government.
Next on the other side of Dolmabahce Palace is a small gallery ( the Istanbul Painting and Sculpture Museum) with a good collection of Turkish artists but be careful. If you are at the ferry terminal, you have gone too far. You can reach this from istanbul Modern by public transport. After you finish here you can either have a late lunch in Besiktas or take public transport to the Sakip Sabanci Museum in Emirgan.
There are actually two museums here. One hosts mostly touring shows (Picasso, Rodin etc. ) and the other hosts a permanent gallery of caligraphy and a history of the museum. Both are worth the time. This is one of the most beautiful museums in the world. The grounds are relaxing and verdant.
After you have finished visiting the exhibits, there is an excellent gift shop and a good coffee shop (located on the roof patio of the museum).
If you own or manage Sakip Sabanci Museum, register now for free tools to enhance your listing, attract new reviews, and respond to reviewers.