There is no existing translator that can import that, no, though it wouldn't be terribly hard to write one (you could look e.g. at the MARCXML translator as a template on how to read XML, but you wouldn't need to call on another translator - alternatively, you can look at the part of the Primo translator that imports XML).

If you have larger code snippets you want to post it typically makes sense to put them as a public gist on gist.github.com and link to them.

I almost succeeded in importing from Excel to Zotero via... BibTeX format. No need to write translator, to code etc. Very simple solution to average (not dumb :)) user.

There: https://groups.google.com/forum/?fromgroups=#!msg/comp.text.tex/mnG8n4iwrM4/R8L5aGeI4c0J I found simple solution:

Suppose you have your excel table
like this:
msp82 Milner The Pi Calculus
ws01 Wischik Explicit Fusion Machine
then you could make a fourth column to the right of these with the formula
="@Article{"&A1&", author="""&B1&""", title="""&C1&"""}"
Then simply select this right hand column, and paste it into a text file,
and Hey Presto! you have your bibtex without the need for any intermediate
programs.

And it works like a charm after some modifications to my needs.

But I can't get imported "Access date", "Archive" and "Library catalog" fields. Latter two haven't mapping in translator (is there any possibility to do that for my needs only? How to map them, to which BibTeX fields?).

And I don't understand, what is wrong with "Access date" field. It exports from Excel to txt in such form:
lastchecked="2002 11 27", [y m d format]
But Zotero field "Accessed" is empty after importing that txt. All other fields imports well. What is wrong?

Thank you. I solved all problems except one: how to export properly formatted dates from Excel. Zotero can import only such format of date:
lastchecked="2002-11-27"
So I converted cells with dates from text to date format. And now I am getting such a format after exporting from Excel:
lastchecked="37587"
(number of date, but not date itself). How export dates from Excel keeping their format?

All the problems are solved now and all references (about one thousand) are transferred from Excel to Zotero.
I deliberately mapped BibTeX fields to suitable Zotero fields in in BibTex translator so all data was transferred.

My steps to transfer access dates was to change appropriate Excel field from general to date format (essential was conversion "Data -> text to columns" from there: http://www.ozgrid.com/Excel/convert-excel-date-formats.htm ), format all dates and then convert them to text by such formula: =CONCATENATE(TEXT(A2;"yyyy-mm-dd")) (from there: http://www.ozgrid.com/forum/showthread.php?t=59850 ).

There were some problems with author names. Names were inverted - last name first. So I changed translator line fromcreator = Zotero.Utilities.cleanAuthor(name, field, false); to creator = Zotero.Utilities.cleanAuthor(name, field, true); After that last names and first names were recognized properly.

Also author names were separated by semicolons in my Excel sheet. So I changed translator line form } else if(field == "author" || field == "editor" || field == "translator") {
var names = value.split(/ and /i);to} else if(field == "author" || field == "editor" || field == "translator") {
var names = value.split(";");and after that all authors were separated properly.

I think, such way of importing references from Excel to Zotero is quite convenient: there is no need for EndNote as intermediary; only simple and easily adjustable Excel formulas, quite good BibTeX translator. Maybe it is worth to prepare some "how to"?

So, let's assume, that Excel sheet is like this:
| A | B | C
1 |Call No | Author | Title
2 | 1795 x | Husovianas M. | Giesmė apie stumbrą
You want to copy second line. So then you should make a fourth column (row D) to the right of these in second line with the formula
="@book{lccn="""&A2&""", author="""&B2&""", title="""&C2&"""}"
There can be other types of references (article, chapter etc.) instead of "book" and other fields (and more of the fields, of course). BibTeX names you can read from Zotero BibTeX translator: types of reference (section "var bibtex2zoteroTypeMap") and field names (sections "var fieldMap" and "var inputFieldMap"). So you can assign right field name to the row. Call number is called "lccn" in BibTeX so I assigned to A row "lccn" value and so on. Number besides A, B, C in formula refers to Excel line number.
If there are more than one line of references, you should point with mouse to the bottom right corner of cell D2 (in which formula resides) and drag it downward D row until all lines with your references are covered. Excel converts formula according to the lines (A2 becomes A3 in a third line and so on), so you don't need rewrite formula manually.
After that you should copy only D row of Excel sheet (that part of it with formulas), paste it to simple txt file (if there are unicode characters in references save it in utf-8, not ANSI) and select that file to import with Zotero. That's it.

There are other tools for importing reference lists into Zotero listed here
http://www.zotero.org/support/kb/importing_formatted_bibliographies
I've added text2bib - thanks.

If interested, another solution to export Excel ou Access file in RIS format compatible with Zotero

=> https://forums.zotero.org/discussion/12649/import-from-excel-and-access-databases/

What format are you using for import? BibTeX? RIS?

What does the data look like ?

That's bibtex

There's no fixed mapping for all of those fields, it depends on the item type, and you would have to take care to escape some characters properly. I think RIS is going to be easier.

I would think RIS would be easier, but I don't know anything about excel automation, and I don't know enough about RIS to suggest a field mapping.I am very familiar with bibtex though and there is not a bibtex-field-to-zotero-field mapping there, it is going to vary by zotero item type, which is going to make a bibtex export from excel more complicated.

I think your best bet would be to create some entries in Zotero the way you'd want them to look like after import, export them to bibtex/RIS, and then look whether you can re-create those from your excel file. If you're going with bibtex,I'd recommend installing my "Better BibTeX" plugin, as it does more detailed conversions, but even there I can't guarantee that entries you export with it import precisely the same. Bibtex and zotero use slightly different concepts, and translations are not always lossless.