Thienopyrimidine derivatives

4-Substituted-thieno[2,3-d], [3,2-d], and [3,4-d]pyrimidines having fungicidal, insecticidal, and miticidal utility are disclosed. Related 3-substituted-thieno[2,3-d], [3,2-d], and [3,4-d]pyrimidin-4-(3H)-imines are useful as fungicides, insecticides, and miticides, and also as intermediates in preparing N-substituted-thienopyrimidin-4-amines. Related o-cyano-amidines are useful as intermediates in preparing the 3-substituted-thieno[2,3-d], [3,2-d], and [3,4-d]pyrimidin-4-(3H)-imines.