Try the Materials Informatics Toolkit, which is designed to easily handle SMILES data. This and other helpful add-ins are available in the JMP® Marketplace
I wolud like to write into one table cell long string. Is there any option to write the string in 2 lines and put it into same cell (similar to Alt+enter in excel)?
JMP does not have such an option. The row height can be changed, which will allow long strings to wrap within a cell, however, when you change one rows height, all rows will be changed to the same height.