That works. Thanks again a lot, I owe you one!

My installation doesn't recognize the command ReIm. The help window gives me the info: "AlgebraReIm was available as an add-on package in previous versions of Mathematica and is now available on the web at library.wolfram.com/infocenter/MathSource/6759." The m-file that I can download under this link contains the text:

(* ::Package:: *)
(* :Title: ReIm *)
(* :Summary:
The ReIm package is obsolete. Use instead functionality
provided by Assuming, Assumptions, ComplexExpand, Refine,
and similar functions.
*)
(* :Copyright: Copyright 1990-2007, Wolfram Research, Inc.  *)
Message[General::obspkg,"Algebra`ReIm`"];
BeginPackage["Algebra`ReIm`"]
(*ReIm::obslt =
"The ReIm package is obsolete. Use instead functionality provided by \
Assuming, ComplexExpand, Refine, and similar functions.";*)
EndPackage[]

Seems that ReIm is too old. I tried (and tried to understand) the mentioned commands but none worked.

Thanks, Rohit! I knew about ComplexListPlot in V12 already, but I'm honestly surprised that there is no simply solution in earlier versions. (Maybe in an add-on?) Thanks again!

Hello Rohit, thanks for your reply.

Pole = {1,-1-I,-1+I}

after import and split. Three little complex numbers. Nothing more. The final graphic should be looking similar to this: