A Defendant's Motion for Sanctions is usually offered in the pretrial stages of a case. It is usually done where the State has failed to comply with discovery requests. For instances, if the State the was ordered to turn over a drug certificate at a certain date and failed to do such then the defense would ask for sanctions. In that case the sanctions would probably be to exclude the evidence.
A criminal defense attorney would file a Motion to Impose Sanctions as a strategy to force the prosecutor to do something or produce evidence. Generally the motion asks the Court to either compel the prosecutor to give the information to the defense, or not allow them to use that evidence at trial.