The preparation of [closo-1-CB9H8-1-COOH-10-(4-C3H7C5H9S)] as intermediate to polar liquid crystals

► The preparation of [closo-1-CB9H8-1-COOH-10-I]− was optimized for 40 g of B10H14. ► The iodo acid was transformed to sulfonium acid [closo-1-CB9H8-1-COOH-10-(4-C3H7C5H9S)]. ► The overall yield of the sulfonium acid is about 1.3% based on B10H14. ► An ester of 4-butoxyphenol of the sulfonium acid exhibits a nematic phase.