# How do you name a bicyclo compound with a fused benzene ring?

What is the IUPAC rule for naming a bicyclo compound with a fused benzene ring? Are you required to state the number of double bonds by adding something like 2,4,6-ene to the name or do benzene rings have a specific name ?

For example:

What will this compound be named? Will it be bicyclo[4.3.0]non 1,2,4 triene or is there some specific rule for fused benzene rings, as I stated before?

• This is, derived from the stem compound, indene, $\text{2,3-dihydro-1}​\textit{H}\text{​-indene}.$ May 14 '21 at 4:49
• One follows the rules for fused rings. Years ago there were different acceptable approaches. And many structures can have traditional name (in the discussion at least, for identification, as it goes with data such as mp, H-NMR, elemental analysis,... perhaps one has to be stricter. But name as carbazole, naphthalene, indene, etc are OK. May 14 '21 at 9:14
• I didn't say I apply Hantzsch-Widman here. I followed @Long's comment "Please don't answer in comments". May 19 '21 at 21:04