Methods for the syntheses of 4-substituted isothiochromenes and 1,1-disubstituted 1,3-dihydrobenzo[c]thiophenes have been developed. Thus, treatment of alpha-substituted o-[(tert-butylsulfanyl)methyl]styrenes, derived from alpha-substituted o-bromostyrenes using an easily operated four-step sequence, with iodine in the presence of sodium hydrogencarbonate gave isothiochromene derivatives. These tert-butyl sulfides were treated with concentrated hydrobromic acid to give 1,3-dihydrobenzo[c]thiophene derivatives.