 During the same period, he collaborated with a number of musicians, including fellow singer-songwriter Bülent Ortaçgil, environmental activist and singer Leman Sam, and fretless guitarist pioneer Erkan Oğur.Kızılok suffered a heart attack in 1998, the year he finished his last studio album, "Mustafa Kemal – Devrimcinin Güncesi" (Mustafa Kemal – A Revolutionary's Diary).Although he was working on a new album, preliminarily entitled "Suya Yazılan Şarkılar", this never was to be released.