What is the legal ruling on a man carrying materials with the intention of trading them, believing them to be stimulants and narcotics, then it becomes clear after analysis that they are not?

It is not permissible for a man to carry materials that he believes to be forbidden for sale and trade. He incurs sin by doing so, even if it later turns out that they are not forbidden. This is based on the legal maxim, "Matters are judged by their intentions." If someone commits a permissible act believing it to be unlawful, such as a man who has intercourse with a woman he believes to be a stranger, but she turns out to be his wife, he is subject to the ruling of a transgressor due to his audacity against God. However, he will not be punished in the Hereafter with the punishment of one who commits a major sin. As for someone who has intercourse with a strange woman, believing her to be his wife, none of the punishments for fornication apply to him, considering his intention and purpose.