Incorrect syntax near the keyword 'SCHEMA'

If you try to execute:

IF NOT EXISTS (SELECT * FROM sys.schemas WHERE name = N'NewSchemaName')

       CREATE SCHEMA [NewSchemaName] AUTHORIZATION [dbo]

GO

You will get this error message:

Msg 156, Level 15, State 1, Line 2

Incorrect syntax near the keyword 'SCHEMA'.

And it although this command will success:

CREATE SCHEMA [NewSchemaName] AUTHORIZATION [dbo]

So why we’ve got the error?

Because schema creation must be the first command in a batch.

A solution:
Run it as dynamic SQL:

IF NOT EXISTS (SELECT * FROM sys.schemas WHERE name = N'NewSchemaName')

       EXEC sp_executesql N'CREATE SCHEMA [NewSchemaName] AUTHORIZATION [dbo]'

GO