McConnell almost worked in telecommunications, but was convinced by Ferguson to join Strathclyde's new Centre for Biophotonics. She became interested in biomedical research and increasingly aware of the limitations of commercial imaging. Here she worked with Alison Gurney on the development of confocal, multi-photon wide-field microscopes. Gurney encouraged McConnell to apply for fellowships, and she was a Royal Society of Edinburgh and Research Councils UK (RCUK) postdoctoral fellow. She developed the world's first white light supercontinuum laser that could be used for confocal microscopy, as well as laser scanning fluorescence microscopy. She attended the European Molecular Biology Laboratory (EMBL) Practical Course in Advanced Optical Microscopy in Plymouth, which she has continued to support throughout her academic career.