2-Cyano(phenylsulfinyl-, p-nitrophenyl-, or o-nitrophenyl-)methylthiophenyl isocyanides were synthesized from 2-aminobenzenethiols and were shown to undergo ringclosure to 2,4-disubstituted 4H-1,4-benzothiazine derivatives by deprotonation of the hydrogen adjacent to the sulfur atom with sodium hydride or potassium tert-butoxide, followed by trapping with various electrophiles.