Here is a transcript of v103 session: Welcome to MzScheme version 103.1 (using locale), Copyright (c) 1995-2000 PLT (Matthew Flatt) > (string=? "" (string (integer->char 0))) #t > (string-ci=? "" (string (integer->char 0))) #f > (string-length (string (integer->char 0))) 1 > Is it a bug? AT