The fifth edition of the Hot Topics in Contemporary Crystallography advanced workshop (HTCC5), this time co-funded by Croatian Science Foundation, through the calixDNA project, and supported by European Crystallographic Association and International Union of Crystallography, was held in Sheraton Dubrovnik Riviera Conference centre in Mlini, from 16^th to 21^st April 2023. The workshop is tradionally organized be the Croatian Association of Crystallography, and chair of the international Organizing committee was dr. Aleksandar Višnjevac, head of the calixDNA project. The HTCC5 was generously sponsored by Bruker, Formulatrix, Douglas Instruments, Xtal Concepts, Anton Paar, Mitegen, Oxford Cryosystems, Dectris and Rigaku.

The workshop gathered 52 registered participants from 16 countries (Algeria, Austria, Croatia, Czech Republic, France, Germany, Italy, Ireland, Jordan, Poland, Serbia, Sweden, Slovenia, Turkey, UK, and Ukraine) out of which 28 students, 11 lecturers, 7 sponsor representatives, 2 accompanying persons and 4 organizers. 13 students (from Algeria, Austria, Czech Republic, Poland, Croatia, Serbia, Sweden and Ukraine) received bursaries to cover, partially or entirely, their registration fees, accommodation expenses and travel expenses. The bursaries were generously funded by International Union of Crystallography, Croatian Association of Crystallographers and European Crystallographic Association.

Over four intensive working days, two of which extended to 11:00 PM, four “hot topics” (macromolecular crystallization, processing of the diffraction data, structural databases, and visualization of the macromolecules) were thoroughly covered through 15 lectures, 14 tutorials and one demonstration/presentation. In addition to this, the Douglas Instruments and Xtal Concepts Activity “Bring your own sample” enabled students the touch-on experience in applying advanced techniques (dynamic light scattering, microseeding) on their own brought samples with a goal (that, in quite a few cases, was indeed achieved) to produce high quality single crystals, suitable for diffraction measurements. Finally, within the interactivity scheme of the HTCC5, students, themselves, presented 18 posters and 15 five-minutes long discussion triggering presentations (DTP). THe best presentations were awarded with a monetary 100 € award which was generously provided by Dectris (best DTP) and Croatian Association of Crystallographers (best poster). he best poster prize was awarded to Daniel Mokos, for his poster entitled “Crystal structure and proposed mechanism of A622 homologues from the nicotine biosynthesis pathway”, while Marika Majerova was awarded for the best discussion triggering presentation for her presentation entitled “An extant enzyme with dual dehalogenase‒luciferase function”.