Studies on lndigoid Dyes. Part Xll. 2-(4-lodo) Thionaphthene-3'-Indole Indigos, 2-(4-lodo) Thionaphthene-8'-Acenaphthylene Indigos and 2-( 4/7- lodo) Thionaphthene-l'-Aceanthrene Indigos - AJOY KUMAR DAS (1974)