It is opensource and freeware in this stage of development
SDF or Structures Data File is a common file format developed by Molecular Design Limited to handle a list of molecular structures with associated properties. Its description can be found
here. Some chemical and pharmaceutical companies offer their catalogues of products in SDF format, i.e. Advamacs.
If you want to create an SDF of your compounds you need a chemical database with such ability, like this one.
Use File-> OpenSDF or press Ctrl+o in order to open an SDF. SDFReader allows to browse structures of compounds contained in SDF. It also makes it possible to save data in sqlite3 database format, then search them according to given criteria. In order to activate searching you need first open SDF and then save sqlite database or open previously saved one.
The program was written in Tcl/Tk scripting language which made it easy to prepare standalone executables for Windows and Linux. It uses Sqlite database library for searching data. The program is currently in development stage, so errors can be expected.
Windows executable - SDFReader-2013-11-25.exe - 1.5MB
Linux executable - SDFReader-2010-11-25 - 2.3MB
Sources - SDFReader.zip - 14KB
2013 November 25 - a bug was fixed that caused crashing with some SDFs.
2010 February 2 - a bug was fixed that blocked drawing structures when stereo data was not present in molfiles.
2009 July 31 - SDFReader was annouced to the world.